Add and Subtract Square Roots

Add and Subtract Like Square Roots

Think about adding like terms with variables as you do the next few examples. When you have like radicands, you just add or subtract the coefficients. When the radicands are not like, you cannot combine the terms.

Example

Try it.

Simplify: \(2\sqrt{2}-7\sqrt{2}\).

Solution

	\(2\sqrt{2}-7\sqrt{2}\)
Since the radicals are like, we subtract the coefficients.	\(-5\sqrt{2}\)

Example

Try it.

Simplify: \(3\sqrt{y}+4\sqrt{y}\).

Solution

	\(3\sqrt{y}+4\sqrt{y}\)
Since the radicals are like, we add the coefficients.	\(7\sqrt{y}\)

Example

Try it.

Simplify: \(4\sqrt{x}-2\sqrt{y}\).

Solution

	\(4\sqrt{x}-2\sqrt{y}\)
Since the radicals are not like, we cannot subtract them. We leave the expression as is.	\(4\sqrt{x}-2\sqrt{y}\)

Example

Try it.

Simplify: \(5\sqrt{13}+4\sqrt{13}+2\sqrt{13}\).

Solution

	\(5\sqrt{13}+4\sqrt{13}+2\sqrt{13}\)
Since the radicals are like, we add the coefficients.	\(11\sqrt{13}\)

Example

Try it.

Simplify: \(2\sqrt{6}-6\sqrt{6}+3\sqrt{3}\).

Solution

	\(2\sqrt{6}-6\sqrt{6}+3\sqrt{3}\)
Since the first two radicals are like, we subtract their coefficients.	\(-4\sqrt{6}+3\sqrt{3}\)

Example

Try it.

Simplify: \(2\sqrt{5n}-6\sqrt{5n}+4\sqrt{5n}\).

Solution

	\(2\sqrt{5n}-6\sqrt{5n}+4\sqrt{5n}\)
Since the radicals are like, we combine them.	\(0\sqrt{5n}\)
Simplify.	0

When radicals contain more than one variable, as long as all the variables and their exponents are identical, the radicals are like.

Example

Try it.

Simplify: \(\sqrt{3xy}+5\sqrt{3xy}-4\sqrt{3xy}\).

Solution

	\(\sqrt{3xy}+5\sqrt{3xy}-4\sqrt{3xy}\)
Since the radicals are like, we combine them.	\(2\sqrt{3xy}\)

Add and Subtract Square Roots that Need Simplification

Remember that we always simplify square roots by removing the largest perfect-square factor. Sometimes when we have to add or subtract square roots that do not appear to have like radicals, we find like radicals after simplifying the square roots.

Example

Try it.

Simplify: \(\sqrt{20}+3\sqrt{5}\).

Solution

	\(\sqrt{20}+3\sqrt{5}\)
Simplify the radicals, when possible.	\(\sqrt{4}\cdot \sqrt{5}+3\sqrt{5}\)
	\(2\sqrt{5}+3\sqrt{5}\)
Combine the like radicals.	\(5\sqrt{5}\)

Example

Try it.

Simplify: \(\sqrt{48}-\sqrt{75}\).

Solution

	\(\sqrt{48}-\sqrt{75}\)
Simplify the radicals.	\(\sqrt{16}\cdot \sqrt{3}-\sqrt{25}\cdot \sqrt{3}\)
	\(4\sqrt{3}-5\sqrt{3}\)
Combine the like radicals.	\(\text{-}\sqrt{3}\)

Just like we use the Associative Property of Multiplication to simplify \(5(3x)\) and get \(15x\), we can simplify \(5(3\sqrt{x})\) and get \(15\sqrt{x}\). We will use the Associative Property to do this in the next example.

Example

Try it.

Simplify: \(5\sqrt{18}-2\sqrt{8}\).

Solution

	\(5\sqrt{18}-2\sqrt{8}\)
Simplify the radicals.	\(5\cdot \sqrt{9}\cdot \sqrt{2}-2\cdot \sqrt{4}\cdot \sqrt{2}\)
	\(5\cdot 3\cdot \sqrt{2}-2\cdot 2\cdot \sqrt{2}\)
	\(15\sqrt{2}-4\sqrt{2}\)
Combine the like radicals.	\(11\sqrt{2}\)

Example

Try it.

Simplify: \(\frac{3}{4}\sqrt{192}-\frac{5}{6}\sqrt{108}\).

Solution

	\(\frac{3}{4}\sqrt{192}-\frac{5}{6}\sqrt{108}\)
Simplify the radicals.	\(\frac{3}{4}\sqrt{64}\cdot \sqrt{3}-\frac{5}{6}\sqrt{36}\cdot \sqrt{3}\)
	\(\frac{3}{4}\cdot 8\cdot \sqrt{3}-\frac{5}{6}\cdot 6\cdot \sqrt{3}\)
	\(6\sqrt{3}-5\sqrt{3}\)
Combine the like radicals.	\(\sqrt{3}\)

Example

Try it.

Simplify: \(\frac{2}{3}\sqrt{48}-\frac{3}{4}\sqrt{12}\).

Solution

	\(\frac{2}{3}\sqrt{48}-\frac{3}{4}\sqrt{12}\)
Simplify the radicals.	\(\frac{2}{3}\sqrt{16}\cdot \sqrt{3}-\frac{3}{4}\sqrt{4}\cdot \sqrt{3}\)
	\(\frac{2}{3}\cdot 4\cdot \sqrt{3}-\frac{3}{4}\cdot 2\cdot \sqrt{3}\)
	\(\frac{8}{3}\sqrt{3}-\frac{3}{2}\sqrt{3}\)
Find a common denominator to subtract the coefficients of the like radicals.	\(\frac{16}{6}\sqrt{3}-\frac{9}{6}\sqrt{3}\)
Simplify.	\(\frac{7}{6}\sqrt{3}\)

Condensed: the full section is in OpenStax Elementary Algebra 2e.

Key Concepts

• To add or subtract like square roots, add or subtract the coefficients and keep the like square root.
• Sometimes when we have to add or subtract square roots that do not appear to have like radicals, we find like radicals after simplifying the square roots.

Add and Subtract Square Roots

Add and Subtract Like Square Roots

In the following exercises, simplify.

Try it.

\(8\sqrt{2}-5\sqrt{2}\)

Solution

\(3\sqrt{2}\)

Try it.

\(7\sqrt{2}-3\sqrt{2}\)

Try it.

\(3\sqrt{5}+6\sqrt{5}\)

Solution

\(9\sqrt{5}\)

Try it.

\(4\sqrt{5}+8\sqrt{5}\)

Try it.

\(9\sqrt{7}-10\sqrt{7}\)

Solution

\(\text{-}\sqrt{7}\)

Try it.

\(11\sqrt{7}-12\sqrt{7}\)

Try it.

\(7\sqrt{y}+2\sqrt{y}\)

Solution

\(9\sqrt{y}\)

Try it.

\(9\sqrt{n}+3\sqrt{n}\)

Try it.

\(\sqrt{a}-4\sqrt{a}\)

Solution

\(-3\sqrt{a}\)

Try it.

\(\sqrt{b}-6\sqrt{b}\)

Try it.

\(5\sqrt{c}+2\sqrt{c}\)

Solution

\(7\sqrt{c}\)

Try it.

\(7\sqrt{d}+2\sqrt{d}\)

Try it.

\(8\sqrt{a}-2\sqrt{b}\)

Solution

\(8\sqrt{a}-2\sqrt{b}\)

Try it.

\(5\sqrt{c}-3\sqrt{d}\)

Try it.

\(5\sqrt{m}+\sqrt{n}\)

Solution

\(5\sqrt{m}+\sqrt{n}\)

Try it.

\(\sqrt{n}+3\sqrt{p}\)

Try it.

\(8\sqrt{7}+2\sqrt{7}+3\sqrt{7}\)

Solution

\(13\sqrt{7}\)

Try it.

\(6\sqrt{5}+3\sqrt{5}+\sqrt{5}\)

Try it.

\(3\sqrt{11}+2\sqrt{11}-8\sqrt{11}\)

Solution

\(-3\sqrt{11}\)

Try it.

\(2\sqrt{15}+5\sqrt{15}-9\sqrt{15}\)

Try it.

\(3\sqrt{3}-8\sqrt{3}+7\sqrt{5}\)

Solution

\(-5\sqrt{3}+7\sqrt{5}\)

Try it.

\(5\sqrt{7}-8\sqrt{7}+6\sqrt{3}\)

Try it.

\(6\sqrt{2}+2\sqrt{2}-3\sqrt{5}\)

Solution

\(8\sqrt{2}-3\sqrt{5}\)

Try it.

\(7\sqrt{5}+\sqrt{5}-8\sqrt{10}\)

Try it.

\(3\sqrt{2a}-4\sqrt{2a}+5\sqrt{2a}\)

Solution

\(4\sqrt{2a}\)

Try it.

\(\sqrt{11b}-5\sqrt{11b}+3\sqrt{11b}\)

Try it.

\(8\sqrt{3c}+2\sqrt{3c}-9\sqrt{3c}\)

Solution

\(\sqrt{3c}\)

Try it.

\(3\sqrt{5d}+8\sqrt{5d}-11\sqrt{5d}\)

Try it.

\(5\sqrt{3ab}+\sqrt{3ab}-2\sqrt{3ab}\)

Solution

\(4\sqrt{3ab}\)

Try it.

\(8\sqrt{11cd}+5\sqrt{11cd}-9\sqrt{11cd}\)

Try it.

\(2\sqrt{pq}-5\sqrt{pq}+4\sqrt{pq}\)

Solution

\(\sqrt{pq}\)

Try it.

\(11\sqrt{2rs}-9\sqrt{2rs}+3\sqrt{2rs}\)

Add and Subtract Square Roots that Need Simplification

In the following exercises, simplify.

Try it.

\(\sqrt{50}+4\sqrt{2}\)

Solution

\(9\sqrt{2}\)

Try it.

\(\sqrt{48}+2\sqrt{3}\)

Try it.

\(\sqrt{80}-3\sqrt{5}\)

Solution

\(\sqrt{5}\)

Try it.

\(\sqrt{28}-4\sqrt{7}\)

Try it.

\(\sqrt{27}-\sqrt{75}\)

Solution

\(-2\sqrt{3}\)

Try it.

\(\sqrt{72}-\sqrt{98}\)

Try it.

\(\sqrt{48}+\sqrt{27}\)

Solution

\(7\sqrt{3}\)

Try it.

\(\sqrt{45}+\sqrt{80}\)

Try it.

\(2\sqrt{50}-3\sqrt{72}\)

Solution

\(-8\sqrt{2}\)

Try it.

\(3\sqrt{98}-\sqrt{128}\)

Try it.

\(2\sqrt{12}+3\sqrt{48}\)

Solution

\(16\sqrt{3}\)

Try it.

\(4\sqrt{75}+2\sqrt{108}\)

Try it.

\(\frac{2}{3}\sqrt{72}+\frac{1}{5}\sqrt{50}\)

Solution

\(5\sqrt{2}\)

Try it.

\(\frac{2}{5}\sqrt{75}+\frac{3}{4}\sqrt{48}\)

Try it.

\(\frac{1}{2}\sqrt{20}-\frac{2}{3}\sqrt{45}\)

Solution

\(\text{-}\sqrt{5}\)

Try it.

\(\frac{2}{3}\sqrt{54}-\frac{3}{4}\sqrt{96}\)

Try it.

\(\frac{1}{6}\sqrt{27}-\frac{3}{8}\sqrt{48}\)

Solution

\(\text{-}\sqrt{3}\)

Try it.

\(\frac{1}{8}\sqrt{32}-\frac{1}{10}\sqrt{50}\)

Try it.

\(\frac{1}{4}\sqrt{98}-\frac{1}{3}\sqrt{128}\)

Solution

\(-\frac{11}{12}\sqrt{2}\)

Try it.

\(\frac{1}{3}\sqrt{24}+\frac{1}{4}\sqrt{54}\)

Try it.

\(\sqrt{72{a}^{5}}-\sqrt{50{a}^{5}}\)

Solution

\({a}^{2}\sqrt{2a}\)

Try it.

\(\sqrt{48{b}^{5}}-\sqrt{75{b}^{5}}\)

Try it.

\(\sqrt{80{c}^{7}}-\sqrt{20{c}^{7}}\)

Solution

\(2{c}^{3}\sqrt{5c}\)

Try it.

\(\sqrt{96{d}^{9}}-\sqrt{24{d}^{9}}\)

Try it.

\(9\sqrt{80{p}^{4}}-6\sqrt{98{p}^{4}}\)

Solution

\(36{p}^{2}\sqrt{5}-42{p}^{2}\sqrt{2}\)

Try it.

\(8\sqrt{72{q}^{6}}-3\sqrt{75{q}^{6}}\)

Try it.

\(2\sqrt{50{r}^{8}}+4\sqrt{54{r}^{8}}\)

Solution

\(10{r}^{4}\sqrt{2}+12{r}^{4}\sqrt{6}\)

Try it.

\(5\sqrt{27{s}^{6}}+2\sqrt{20{s}^{6}}\)

Try it.

\(3\sqrt{20{x}^{2}}-4\sqrt{45{x}^{2}}+5x\sqrt{80}\)

Solution

\(14x\sqrt{5}\)

Try it.

\(2\sqrt{28{x}^{2}}-\sqrt{63{x}^{2}}+6x\sqrt{7}\)

Try it.

\(3\sqrt{128{y}^{2}}+4y\sqrt{162}-8\sqrt{98{y}^{2}}\)

Solution

\(4y\sqrt{2}\)

Try it.

\(3\sqrt{75{y}^{2}}+8y\sqrt{48}-\sqrt{300{y}^{2}}\)

Mixed Practice

Try it.

\(2\sqrt{8}+6\sqrt{8}-5\sqrt{8}\)

Solution

\(6\sqrt{2}\)

Try it.

\(\frac{2}{3}\sqrt{27}+\frac{3}{4}\sqrt{48}\)

Try it.

\(\sqrt{175{k}^{4}}-\sqrt{63{k}^{4}}\)

Solution

\(2{k}^{2}\sqrt{7}\)

Try it.

\(\frac{5}{6}\sqrt{162}+\frac{3}{16}\sqrt{128}\)

Try it.

\(2\sqrt{363}-2\sqrt{300}\)

Solution

\(2\sqrt{3}\)

Try it.

\(\sqrt{150}+4\sqrt{6}\)

Try it.

\(9\sqrt{2}-8\sqrt{2}\)

Solution

\(\sqrt{2}\)

Try it.

\(5\sqrt{x}-8\sqrt{y}\)

Try it.

\(8\sqrt{13}-4\sqrt{13}-3\sqrt{13}\)

Solution

\(\sqrt{13}\)

Try it.

\(5\sqrt{12{c}^{4}}-3\sqrt{27{c}^{6}}\)

Try it.

\(\sqrt{80{a}^{5}}-\sqrt{45{a}^{5}}\)

Solution

\({a}^{2}\sqrt{5a}\)

Try it.

\(\frac{3}{5}\sqrt{75}-\frac{1}{4}\sqrt{48}\)

Try it.

\(21\sqrt{19}-2\sqrt{19}\)

Solution

\(19\sqrt{19}\)

Try it.

\(\sqrt{500}+\sqrt{405}\)

Try it.

\(\frac{5}{6}\sqrt{27}+\frac{5}{8}\sqrt{48}\)

Solution

\(5\sqrt{3}\)

Try it.

\(11\sqrt{11}-10\sqrt{11}\)

Try it.

\(\sqrt{75}-\sqrt{108}\)

Solution

\(\text{-}\sqrt{3}\)

Try it.

\(2\sqrt{98}-4\sqrt{72}\)

Try it.

\(4\sqrt{24{x}^{2}}-\sqrt{54{x}^{2}}+3x\sqrt{6}\)

Solution

\(8x\sqrt{6}\)

Try it.

\(8\sqrt{80{y}^{6}}-6\sqrt{48{y}^{6}}\)

Condensed: the full section is in OpenStax Elementary Algebra 2e.

이제 너 계산기는 이것을 해결하지 않지만, 그 조각은 계산 가능합니다. 아래의 하나를 시도하거나 자신의 것을 입력하십시오.

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먼저 종이에 각각을 시도해 보세요. 확인하기 위해 답을 드러내세요. 확인된 답은 각 단계의 솔버에서 열 수 있습니다.

1. Add: ⓐ \(3x+9x\) ⓑ \(5m+5n\).

   끝내주는 걸 힌트

   답을 드러내세요

   ⓐ \(12x\) ⓑ \(5m+5n\)

2. Simplify: \(\sqrt{50{x}^{3}}\).

   끝내주는 걸 힌트

   답을 드러내세요

   \(5x\sqrt{2x}\)

3. Simplify: \(2\sqrt{2}-7\sqrt{2}\).

   끝내주는 걸 힌트

   답을 드러내세요

   	\(2\sqrt{2}-7\sqrt{2}\)
   Since the radicals are like, we subtract the coefficients.	\(-5\sqrt{2}\)

4. Simplify: \(8\sqrt{2}-9\sqrt{2}\).

   끝내주는 걸 힌트

   답을 드러내세요

   \(\text{-}\sqrt{2}\)

5. Simplify: \(5\sqrt{3}-9\sqrt{3}\).

   끝내주는 걸 힌트

   답을 드러내세요

   \(-4\sqrt{3}\)

6. Simplify: \(3\sqrt{y}+4\sqrt{y}\).

   끝내주는 걸 힌트

   답을 드러내세요

   	\(3\sqrt{y}+4\sqrt{y}\)
   Since the radicals are like, we add the coefficients.	\(7\sqrt{y}\)

7. Simplify: \(2\sqrt{x}+7\sqrt{x}\).

   끝내주는 걸 힌트

   답을 드러내세요

   \(9\sqrt{x}\)

8. Simplify: \(5\sqrt{u}+3\sqrt{u}\).

   끝내주는 걸 힌트

   답을 드러내세요

   \(8\sqrt{u}\)

9. Simplify: \(4\sqrt{x}-2\sqrt{y}\).

   끝내주는 걸 힌트

   답을 드러내세요

   	\(4\sqrt{x}-2\sqrt{y}\)
   Since the radicals are not like, we cannot subtract them. We leave the expression as is.	\(4\sqrt{x}-2\sqrt{y}\)

10. Simplify: \(7\sqrt{p}-6\sqrt{q}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(7\sqrt{p}-6\sqrt{q}\)

11. Simplify: \(6\sqrt{a}-3\sqrt{b}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(6\sqrt{a}-3\sqrt{b}\)

12. Simplify: \(5\sqrt{13}+4\sqrt{13}+2\sqrt{13}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(5\sqrt{13}+4\sqrt{13}+2\sqrt{13}\)
    Since the radicals are like, we add the coefficients.	\(11\sqrt{13}\)

13. Simplify: \(4\sqrt{11}+2\sqrt{11}+3\sqrt{11}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(9\sqrt{11}\)

14. Simplify: \(6\sqrt{10}+2\sqrt{10}+3\sqrt{10}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(11\sqrt{10}\)

15. Simplify: \(2\sqrt{6}-6\sqrt{6}+3\sqrt{3}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(2\sqrt{6}-6\sqrt{6}+3\sqrt{3}\)
    Since the first two radicals are like, we subtract their coefficients.	\(-4\sqrt{6}+3\sqrt{3}\)

16. Simplify: \(5\sqrt{5}-4\sqrt{5}+2\sqrt{6}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\sqrt{5}+2\sqrt{6}\)

17. Simplify: \(3\sqrt{7}-8\sqrt{7}+2\sqrt{5}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(-5\sqrt{7}+2\sqrt{5}\)

18. Simplify: \(2\sqrt{5n}-6\sqrt{5n}+4\sqrt{5n}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(2\sqrt{5n}-6\sqrt{5n}+4\sqrt{5n}\)
    Since the radicals are like, we combine them.	\(0\sqrt{5n}\)
    Simplify.	0

19. Simplify: \(\sqrt{7x}-7\sqrt{7x}+4\sqrt{7x}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(-2\sqrt{7x}\)

20. Simplify: \(4\sqrt{3y}-7\sqrt{3y}+2\sqrt{3y}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\text{-}\sqrt{3y}\)

21. Simplify: \(\sqrt{3xy}+5\sqrt{3xy}-4\sqrt{3xy}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\sqrt{3xy}+5\sqrt{3xy}-4\sqrt{3xy}\)
    Since the radicals are like, we combine them.	\(2\sqrt{3xy}\)

22. Simplify: \(\sqrt{5xy}+4\sqrt{5xy}-7\sqrt{5xy}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(-2\sqrt{5xy}\)

23. Simplify: \(3\sqrt{7mn}+\sqrt{7mn}-4\sqrt{7mn}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(0\)

24. Simplify: \(\sqrt{20}+3\sqrt{5}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\sqrt{20}+3\sqrt{5}\)
    Simplify the radicals, when possible.	\(\sqrt{4}\cdot \sqrt{5}+3\sqrt{5}\)
    	\(2\sqrt{5}+3\sqrt{5}\)
    Combine the like radicals.	\(5\sqrt{5}\)

25. Simplify: \(\sqrt{18}+6\sqrt{2}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(9\sqrt{2}\)

26. Simplify: \(\sqrt{27}+4\sqrt{3}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(7\sqrt{3}\)

27. Simplify: \(\sqrt{48}-\sqrt{75}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\sqrt{48}-\sqrt{75}\)
    Simplify the radicals.	\(\sqrt{16}\cdot \sqrt{3}-\sqrt{25}\cdot \sqrt{3}\)
    	\(4\sqrt{3}-5\sqrt{3}\)
    Combine the like radicals.	\(\text{-}\sqrt{3}\)

28. Simplify: \(\sqrt{32}-\sqrt{18}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\sqrt{2}\)

29. Simplify: \(\sqrt{20}-\sqrt{45}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\text{-}\sqrt{5}\)

30. Simplify: \(5\sqrt{18}-2\sqrt{8}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(5\sqrt{18}-2\sqrt{8}\)
    Simplify the radicals.	\(5\cdot \sqrt{9}\cdot \sqrt{2}-2\cdot \sqrt{4}\cdot \sqrt{2}\)
    	\(5\cdot 3\cdot \sqrt{2}-2\cdot 2\cdot \sqrt{2}\)
    	\(15\sqrt{2}-4\sqrt{2}\)
    Combine the like radicals.	\(11\sqrt{2}\)

31. Simplify: \(4\sqrt{27}-3\sqrt{12}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(6\sqrt{3}\)

32. Simplify: \(3\sqrt{20}-7\sqrt{45}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(-15\sqrt{5}\)

33. Simplify: \(\frac{3}{4}\sqrt{192}-\frac{5}{6}\sqrt{108}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\frac{3}{4}\sqrt{192}-\frac{5}{6}\sqrt{108}\)
    Simplify the radicals.	\(\frac{3}{4}\sqrt{64}\cdot \sqrt{3}-\frac{5}{6}\sqrt{36}\cdot \sqrt{3}\)
    	\(\frac{3}{4}\cdot 8\cdot \sqrt{3}-\frac{5}{6}\cdot 6\cdot \sqrt{3}\)
    	\(6\sqrt{3}-5\sqrt{3}\)
    Combine the like radicals.	\(\sqrt{3}\)

34. Simplify: \(\frac{2}{3}\sqrt{108}-\frac{5}{7}\sqrt{147}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\text{-}\sqrt{3}\)

35. Simplify: \(\frac{3}{5}\sqrt{200}-\frac{3}{4}\sqrt{128}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(0\)

36. Simplify: \(\frac{2}{3}\sqrt{48}-\frac{3}{4}\sqrt{12}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\frac{2}{3}\sqrt{48}-\frac{3}{4}\sqrt{12}\)
    Simplify the radicals.	\(\frac{2}{3}\sqrt{16}\cdot \sqrt{3}-\frac{3}{4}\sqrt{4}\cdot \sqrt{3}\)
    	\(\frac{2}{3}\cdot 4\cdot \sqrt{3}-\frac{3}{4}\cdot 2\cdot \sqrt{3}\)
    	\(\frac{8}{3}\sqrt{3}-\frac{3}{2}\sqrt{3}\)
    Find a common denominator to subtract the coefficients of the like radicals.	\(\frac{16}{6}\sqrt{3}-\frac{9}{6}\sqrt{3}\)
    Simplify.	\(\frac{7}{6}\sqrt{3}\)

37. Simplify: \(\frac{2}{5}\sqrt{32}-\frac{1}{3}\sqrt{8}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\frac{14}{15}\sqrt{2}\)

38. Simplify: \(\frac{1}{3}\sqrt{80}-\frac{1}{4}\sqrt{125}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\frac{1}{12}\sqrt{5}\)

39. Simplify: \(\sqrt{18{n}^{5}}-\sqrt{32{n}^{5}}\).

    끝내주는 걸 힌트

    답을 드러내세요

    	\(\sqrt{18{n}^{5}}-\sqrt{32{n}^{5}}\)
    Simplify the radicals.	\(\sqrt{9{n}^{4}}\cdot \sqrt{2n}-\sqrt{16{n}^{4}}\cdot \sqrt{2n}\)
    	\(3{n}^{2}\sqrt{2n}-4{n}^{2}\sqrt{2n}\)
    Combine the like radicals.	\(\text{-}{n}^{2}\sqrt{2n}\)

40. Simplify: \(\sqrt{32{m}^{7}}-\sqrt{50{m}^{7}}\).

    끝내주는 걸 힌트

    답을 드러내세요

    \(\text{-}{m}^{3}\sqrt{2m}\)

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여기서 사용된 기호

기호를 탭하면 전체 정의, 이미지 및 각 문자의 의미를 확인할 수 있습니다.

\sqrt{x}square root, n-th root
The non-negative number whose square (n-th power) is x.\pmplus or minus
Both signs at once: x = 3 ± 2 means 5 and 1.\neqnot equal
The two sides are different.\leqless/greater than or equal
Inequalities that allow equality; < and > exclude it.|x|absolute value / modulus
Distance from zero: |−3| = 3. For a complex number, distance from the origin.iimaginary unit
i² = −1.\log_b xlogarithm, natural log
The exponent b must be raised to for x; ln uses base e.\mathbb{N}number sets
Naturals, integers, rationals, reals, complex numbers.

어떻게: Add and Subtract Square Roots

1. Add and subtract like square roots
2. Add and subtract square roots that need simplification
3. To add or subtract like square roots, add or subtract the coefficients and keep the like square root.
4. Sometimes when we have to add or subtract square roots that do not appear to have like radicals, we find like radicals after simplifying the square roots.

사람들이 묻는 질문

What does it mean to solve an equation?

To find every value of the unknown that makes both sides equal. Each step is an operation applied to both sides that keeps the solution set the same, until the unknown stands alone.

Why do I sometimes get two answers?

A quadratic can cross the axis twice, so it can have two solutions. A degree-n polynomial has up to n. The graph shows where each one comes from.

How do I know whether to factor or use the quadratic formula?

Try factoring for a few seconds: look for two numbers that multiply to a·c and add to b. If nothing obvious appears, the discriminant b² − 4ac tells you how many real roots there are, and the formula finds them without guessing.

이 페이지의 일부는 다음에서 변경되었습니다. OpenStax Elementary Algebra 2e (CC BY-NC-SA 4.0). 여기서 압축하고 다시 설명; 오류는 우리의. 소스가 비상업적 사용을 위해 라이선스되어 있기 때문에, 이 레슨은 무료이며, 아무것도 판매하지 않으며, 동일한 라이선스로 공유됩니다.

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Linear equationsQuadratic equationsSystems of equationsInequalitiesFactoringExpandingSimplifying expressionsFunctions and graphsExponential and logarithmic equationsPolynomial equationsAbsolute value