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Distributive Property
Simplify expressions using the distributive property
Simplify Expressions Using the Distributive Property
Suppose three friends are going to the movies. They each need \(\text{\$9.25};\) that is, \(9\) dollars and \(1\) quarter. How much money do they need all together? You can think about the dollars separately from the quarters.
They need \(3\) times \(\text{\$9},\) so \(\text{\$27},\) and \(3\) times \(1\) quarter, so \(75\) cents. In total, they need \(\text{\$27.75}.\)
If you think about doing the math in this way, you are using the Distributive Property.
Back to our friends at the movies, we could show the math steps we take to find the total amount of money they need like this:
\[\begin{array}{lll} & 3(9.25) & \\ 3(9 & + & 0.25) \\ 3(9) & + & 3(0.25) \\ 27 & + & 0.75 \\ & 27.75 & \end{array}\]In algebra, we use the Distributive Property to remove parentheses as we simplify expressions. For example, if we are asked to simplify the expression \(3(x+4),\) the order of operations says to work in the parentheses first. But we cannot add \(x\) and \(4,\) since they are not like terms. So we use the Distributive Property,
Example
Try it.
Simplify: \(3(x+4).\)
Solution
| \(3(x+4)\) | |
| Distribute. | \(3\cdot x+3\cdot 4\) |
| Multiply. | \(3x+12\) |
Some students find it helpful to draw in arrows to remind them how to use the Distributive Property. Then the first step in would look like this:
Example
Try it.
Simplify: \(6(5y+1).\)
Solution
| Distribute. | |
| Multiply. |
The distributive property can be used to simplify expressions that look slightly different from \(a(b+c).\) Here are two other forms.
Example
Try it.
Simplify: \(2(x-3).\)
Solution
| Distribute. | |
| Multiply. |
Example
Try it.
Simplify: \(\frac{3}{4}(n+12).\)
Solution
| Distribute. | |
| Simplify. |
Example
Try it.
Simplify: \(8(\frac{3}{8}x+\frac{1}{4}).\)
Solution
| Distribute. | |
| Multiply. |
Example
Try it.
Simplify: \(100(0.3+0.25q).\)
Solution
| Distribute. | |
| Multiply. |
Condensed: the full section is in OpenStax Prealgebra 2e.
Evaluate Expressions Using the Distributive Property
Some students need to be convinced that the Distributive Property always works.
In the examples below, we will practice evaluating some of the expressions from previous examples; in part ⓐ , we will evaluate the form with parentheses, and in part ⓑ we will evaluate the form we got after distributing. If we evaluate both expressions correctly, this will show that they are indeed equal.
Example
Try it.
When \(y=10\) evaluate: ⓐ \(\ 6(5y+1)\) ⓑ \(\ 6\cdot 5y+6\cdot 1.\)
Solution
| ⓐ | |
| \(6(5y+1)\) | |
| Simplify in the parentheses. | \(6(51)\) |
| Multiply. | \(306\) |
| ⓑ | |
| Simplify. | |
| Add. |
Notice, the answers are the same. When \(y=10,\)
\[6(5y+1)=6\cdot 5y+6\cdot 1.\]Try it yourself for a different value of \(y.\)
Example
Try it.
When \(y=3,\) evaluate ⓐ \(\ -2(4y+1)\)ⓑ \(\ -2\cdot 4y+(-2)\cdot 1.\)
Solution
| ⓐ | |
| \(\ -2(4y+1)\) | |
| Simplify in the parentheses. | \(-2(13)\) |
| Multiply. | \(-26\) |
| ⓑ | |
| \(\ -2\cdot 4y+(-2)\cdot 1\) | |
| Multiply. | \(-24-2\) |
| Subtract. | \(-26\) |
| The answers are the same. When \(y=3,\) | \(-2(4y+1)=-8y-2\) |
Example
Try it.
When \(y=35\) evaluate ⓐ \(\ \text{-}(y+5)\) and ⓑ \(\ \text{-}\text{y}-5\) to show that \(-(y+5)=\text{-}\text{y}-5.\)
Solution
| ⓐ | |
| \(\ \text{-}(y+5)\) | |
| Add in the parentheses. | \(-(40)\) |
| Simplify. | \(-40\) |
| ⓑ | |
| \(\ -y-5\) | |
| Simplify. | \(-40\) |
| The answers are the same when \(y=35,\) demonstrating that | \(-(y+5)=\text{-}y-5\) |
Distributive Property
Simplify Expressions Using the Distributive Property
In the following exercises, simplify using the distributive property.
Try it.
\(\frac{1}{2}(n+8)\)
Try it.
\(\frac{1}{3}(u+9)\)
Solution
\(\frac{1}{3}u+3\)
Try it.
\(\frac{1}{4}(3q+12)\)
Try it.
\(\frac{1}{5}(4m+20)\)
Solution
\(\frac{4}{5}m+4\)
Try it.
\(9(\frac{5}{9}y-\frac{1}{3})\)
Try it.
\(10(\frac{3}{10}x-\frac{2}{5})\)
Solution
3x − 4
Try it.
\(12(\frac{1}{4}+\frac{2}{3}r)\)
Try it.
\(12(\frac{1}{6}+\frac{3}{4}s)\)
Solution
2 + 9s
Try it.
\(-2(y+13)\)
Try it.
\(-3(a+11)\)
Solution
−3a − 33
Try it.
\(-7(4p+1)\)
Try it.
\(-9(9a+4)\)
Solution
−81a − 36
Try it.
\(-9(3a-7)\)
Try it.
\(-6(7x-8)\)
Solution
−42x + 48
Try it.
\(5+9(n-6)\)
Try it.
\(12+8(u-1)\)
Solution
8u + 4
Try it.
\(16-3(y+8)\)
Try it.
\(18-4(x+2)\)
Solution
−4x + 10
Try it.
\(4-11(3c-2)\)
Try it.
\(9-6(7n-5)\)
Solution
−42n + 39
Try it.
\(22-(a+3)\)
Try it.
\(-12-(u+10)\)
Try it.
\(-4-(c-10)\)
Solution
−c + 6
Try it.
\((5m-3)-(m+7)\)
Try it.
\((4y-1)-(y-2)\)
Solution
3y + 1
Try it.
\(5(2n+9)+12(n-3)\)
Try it.
\(9(5u+8)+2(u-6)\)
Solution
47u + 60
Try it.
\(9(8x-3)-(-2)\)
Try it.
\(4(6x-1)-(-8)\)
Solution
24x + 4
Try it.
\(14(c-1)-8(c-6)\)
Try it.
\(11(n-7)-5(n-1)\)
Solution
6n − 72
Try it.
\(6(7y+8)-(30y-15)\)
Try it.
\(7(3n+9)-(4n-13)\)
Solution
17n + 76
Evaluate Expressions Using the Distributive Property
In the following exercises, evaluate both expressions for the given value.
Try it.
If \(v=-2,\) evaluate
- ⓐ \(\ 6(4v+7)\)
- ⓑ \(\ 6\cdot 4v+6\cdot 7\)
Try it.
If \(u=-1,\) evaluate
- ⓐ \(\ 8(5u+12)\)
- ⓑ \(\ 8\cdot 5u+8\cdot 12\)
Solution
- ⓐ 56
- ⓑ 56
Try it.
If \(n=\frac{2}{3},\) evaluate
- ⓐ \(\ 3(n+\frac{5}{6})\)
- ⓑ \(\ 3\cdot n+3\cdot \frac{5}{6}\)
Try it.
If \(y=\frac{3}{4},\) evaluate
- ⓐ \(\ 4(y+\frac{3}{8})\)
- ⓑ \(\ 4\cdot y+4\cdot \frac{3}{8}\)
Solution
- ⓐ \(\ \frac{9}{2}\)
- ⓑ \(\ \frac{9}{2}\)
Try it.
If \(y=\frac{7}{12},\) evaluate
- ⓐ \(\ -3(4y+15)\)
- ⓑ \(\ -3\cdot 4y+(-3)\cdot 15\)
Try it.
If \(p=\frac{23}{30},\) evaluate
- ⓐ \(\ -6(5p+11)\)
- ⓑ \(\ -6\cdot 5p+(-6)\cdot 11\)
Solution
- ⓐ −89
- ⓑ −89
Try it.
If \(m=0.4,\) evaluate
- ⓐ \(\ -10(3m-0.9)\)
- ⓑ \(\ -10\cdot 3m-(-10)(0.9)\)
Try it.
If \(n=0.75,\) evaluate
- ⓐ \(\ -100(5n+1.5)\)
- ⓑ \(\ -100\cdot 5n+(-100)(1.5)\)
Solution
- ⓐ −525
- ⓑ −525
Try it.
If \(y=-25,\) evaluate
- ⓐ \(\ -(y-25)\)
- ⓑ \(\ -y+25\)
Try it.
If \(w=-80,\) evaluate
- ⓐ \(\ -(w-80)\)
- ⓑ \(\ -w+80\)
Solution
- ⓐ 160
- ⓑ 160
Try it.
If \(p=0.19,\) evaluate
- ⓐ \(\ -(p+0.72)\)
- ⓑ \(\ -p-0.72\)
Try it.
If \(q=0.55,\) evaluate
- ⓐ \(\ -(q+0.48)\)
- ⓑ \(\ -q-0.48\)
Solution
- ⓐ −1.03
- ⓑ −1.03
Try it.
Simplify \(8(x-\frac{1}{4})\) using the distributive property and explain each step.
Try it.
Explain how you can multiply \(4(\text{\$5.97})\) without paper or a calculator by thinking of \(\text{\$5.97}\) as \(6-0.03\) and then using the distributive property.
Solution
Answers will vary.
ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.
ⓑ What does this checklist tell you about your mastery of this section? What steps will you take to improve?
Condensed: the full section is in OpenStax Prealgebra 2e.
Şimdi sen Hiçbir hesap makinesi bu soruyu çözemez, ama parçaları hesaplanabilir. Aşağıdakilerden birini deneyin veya kendinizinkini yazın.
Pratik (40)
Her birini önce kağıt üzerinde deneyin. Çözümü kontrol etmek için gösterin; doğrulanmış olanlar her adım için çözümleyicide açılabilir.
-
Multiply: \(3(0.25).\)
Cevabı göster
\(0.75\)
-
Simplify: \(10-(-2)(3).\)
Cevabı göster
\(16\)
-
Combine like terms: \(9y+17+3y-2.\)
Cevabı göster
\(12y+15\)
-
Simplify: \(3(x+4).\)
Cevabı göster
\(3(x+4)\) Distribute. \(3\cdot x+3\cdot 4\) Multiply. \(3x+12\) -
Simplify: \(4(x+2).\)
Cevabı göster
4x + 8
-
Simplify: \(6(x+7).\)
Cevabı göster
6x + 42
-
Simplify: \(6(5y+1).\)
Cevabı göster
Distribute. Multiply. -
Simplify: \(9(3y+8).\)
Cevabı göster
27y + 72
-
Simplify: \(5(5w+9).\)
Cevabı göster
25w + 45
-
Simplify: \(2(x-3).\)
Cevabı göster
Distribute. Multiply. -
Simplify: \(7(x-6).\)
Cevabı göster
7x − 42
-
Simplify: \(8(x-5).\)
Cevabı göster
8x − 40
-
Simplify: \(\frac{3}{4}(n+12).\)
Cevabı göster
Distribute. Simplify. -
Simplify: \(\frac{2}{5}(p+10).\)
Cevabı göster
\(\frac{2}{5}p+4\)
-
Simplify: \(\frac{3}{7}(u+21).\)
Cevabı göster
\(\frac{3}{7}u+9\)
-
Simplify: \(8(\frac{3}{8}x+\frac{1}{4}).\)
Cevabı göster
Distribute. Multiply. -
Simplify: \(6(\frac{5}{6}y+\frac{1}{2}).\)
Cevabı göster
5y + 3
-
Simplify: \(12(\frac{1}{3}n+\frac{3}{4}).\)
Cevabı göster
4n + 9
-
Simplify: \(100(0.3+0.25q).\)
Cevabı göster
Distribute. Multiply. -
Simplify: \(100(0.7+0.15p).\)
Cevabı göster
70 + 15p
-
Simplify: \(100(0.04+0.35d).\)
Cevabı göster
4 + 35d
-
Simplify: \(m(n-4).\)
Cevabı göster
Distribute. Multiply. Notice that we wrote \(m\cdot 4\ \text{as}\ 4m.\) We can do this because of the Commutative Property of Multiplication. When a term is the product of a number and a variable, we write the number first.
-
Simplify: \(r(s-2).\)
Cevabı göster
rs − 2r
-
Simplify: \(y(z-8).\)
Cevabı göster
yz − 8y
-
Simplify: \((x+8)p.\)
Cevabı göster
Distribute. -
Simplify: \((x+2)p.\)
Cevabı göster
xp + 2p
-
Simplify: \((y+4)q.\)
Cevabı göster
yq + 4q
-
Simplify: \(-2(4y+1).\)
Cevabı göster
Distribute. Simplify. -
Simplify: \(-3(6m+5).\)
Cevabı göster
−18m − 15
-
Simplify: \(-6(8n+11).\)
Cevabı göster
−48n − 66
-
Simplify: \(-11(4-3a).\)
Cevabı göster
Distribute. Multiply. Simplify. You could also write the result as \(33a-44.\) Do you know why?
-
Simplify: \(-5(2-3a).\)
Cevabı göster
−10 + 15a
-
Simplify: \(-7(8-15y).\)
Cevabı göster
−56 + 105y
-
Simplify: \(-(y+5).\)
Cevabı göster
Multiplying by −1 results in the opposite. Distribute. Simplify. Simplify. -
Simplify: \(-(z-11).\)
Cevabı göster
−z + 11
-
Simplify: \(-(x-4).\)
Cevabı göster
−x + 4
-
Simplify: \(8-2(x+3).\)
Cevabı göster
Distribute. Multiply. Combine like terms. -
Simplify: \(9-3(x+2).\)
Cevabı göster
−3x + 3
-
Simplify: \(7x-5(x+4).\)
Cevabı göster
2x − 20
-
Simplify: \(4(x-8)-(x+3).\)
Cevabı göster
Distribute. Combine like terms.
Burada kullanılan sembolleri
Tüm tanım, resim ve her harfin anlamı için herhangi bir sembolü tıklayın.
Nasıl: Distributive Property
- Simplify expressions using the distributive property
- Evaluate expressions using the distributive property
- If
Sık sorulan sorular
Why does the order of operations matter?
Because 2 + 3 × 4 would otherwise be two different numbers. The convention (brackets, exponents, multiplication and division, addition and subtraction) exists so every reader gets the same value from the same expression.
How do I check an arithmetic answer?
Estimate first (round every number and compute roughly), then compare. If the estimate and the exact answer disagree by more than a little, one of them is wrong. The solver shows every operation, so you can find which line went astray.
Why are fractions harder than decimals?
They are not harder, they are more exact: 1/3 is a precise number, 0.333 is an approximation. Fractions need a common denominator to add, which is the one extra step people trip on.
Parts of this page are adapted from OpenStax Prealgebra 2e (CC BY-NC-SA 4.0). Burada tekrar özetlenmiş ve açıklanmıştır. Hatalar bizim. Kaynağı ticari olmayan kullanım için lisanslanmış olduğu için, bu ders ücretsizdir, hiçbir şey satmaz ve aynı lisans altında paylaşılır.