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Add and Subtract Polynomials
Identify polynomials, monomials, binomials, and trinomials
Identify Polynomials, Monomials, Binomials, and Trinomials
In Evaluate, Simplify, and Translate Expressions, you learned that a term is a constant or the product of a constant and one or more variables. The constant is called a coefficient. When it is of the form \(a{x}^{m},\) where \(a\) is a constant and \(m\) is a whole number, it is called a monomial. A monomial, or a sum and/or difference of monomials, is called a polynomial.
Notice the roots:
- poly- means many
- mono- means one
- bi- means two
- tri- means three
Here are some examples of polynomials:
| Polynomial | \(b+1\) | \(4{y}^{2}-7y+2\) | \(5{x}^{5}-4{x}^{4}+{x}^{3}+8{x}^{2}-9x+1\) |
| Monomial | \(5\) | \(4{b}^{2}\) | \(-9{x}^{3}\) |
| Binomial | \(3a-7\) | \({y}^{2}-9\) | \(17{x}^{3}+14{x}^{2}\) |
| Trinomial | \({x}^{2}-5x+6\) | \(4{y}^{2}-7y+2\) | \(5{a}^{4}-3{a}^{3}+a\) |
Notice that every monomial, binomial, and trinomial is also a polynomial. They are special members of the family of polynomials and so they have special names. We use the words ‘monomial’, ‘binomial’, and ‘trinomial’ when referring to these special polynomials and just call all the rest ‘polynomials’.
Example
Try it.
Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial:
- ⓐ \(\ 8{x}^{2}-7x-9\)
- ⓑ \(\ -5{a}^{4}\)
- ⓒ \(\ {x}^{4}-7{x}^{3}-6{x}^{2}+5x+2\)
- ⓓ \(\ 11-4{y}^{3}\)
- ⓔ \(\ n\)
Solution
| Polynomial | Number of terms | Type | |
| ⓐ | \(8{x}^{2}-7x-9\) | 3 | Trinomial |
| ⓑ | \(-5{a}^{4}\) | 1 | Monomial |
| ⓒ | \({x}^{4}-7{x}^{3}-6{x}^{2}+5x+2\) | 5 | Polynomial |
| ⓓ | \(11-4{y}^{3}\) | 2 | Binomial |
| ⓔ | \(n\) | 1 | Monomial |
Determine the Degree of Polynomials
In this section, we will work with polynomials that have only one variable in each term. The degree of a polynomial and the degree of its terms are determined by the exponents of the variable.
A monomial that has no variable, just a constant, is a special case. The degree of a constant is \(0\)—it has no variable.
Let's see how this works by looking at several polynomials. We'll take it step by step, starting with monomials, and then progressing to polynomials with more terms.
Remember: Any base written without an exponent has an implied exponent of \(1.\)
Example
Try it.
Find the degree of the following polynomials:
- ⓐ \(\ 4x\)
- ⓑ \(\ 3{x}^{3}-5x+7\)
- ⓒ \(\ -11\)
- ⓓ \(\ -6{x}^{2}+9x-3\)
- ⓔ \(\ 8x+2\)
Solution
| ⓐ | \(4x\) |
| The exponent of \(x\) is one. \(x={x}^{1}\) | The degree is 1. |
| ⓑ | \(3{x}^{3}-5x+7\) |
| The highest degree of all the terms is 3. | The degree is 3 |
| ⓒ | \(-11\) |
| The degree of a constant is 0. | The degree is 0. |
| ⓓ | \(-6{x}^{2}+9x-3\) |
| The highest degree of all the terms is 2. | The degree is 2. |
| ⓔ | \(8x+2\) |
| The highest degree of all the terms is 1. | The degree is 1. |
Working with polynomials is easier when you list the terms in descending order of degrees. When a polynomial is written this way, it is said to be in standard form. Look back at the polynomials in . Notice that they are all written in standard form. Get in the habit of writing the term with the highest degree first.
Add and Subtract Monomials
In The Language of Algebra, you simplified expressions by combining like terms. Adding and subtracting monomials is the same as combining like terms. Like terms must have the same variable with the same exponent. Recall that when combining like terms only the coefficients are combined, never the exponents.
Example
Try it.
Add: \(17{x}^{2}+6{x}^{2}.\)
Solution
| \(17{x}^{2}+6{x}^{2}\) | |
| Combine like terms. | \(23{x}^{2}\) |
Example
Try it.
Subtract: \(11n-(-8n).\)
Solution
| \(11n-(-8n)\) | |
| Combine like terms. | \(19n\) |
Example
Try it.
Simplify: \({a}^{2}+4{b}^{2}-7{a}^{2}.\)
Solution
| \({a}^{2}+4{b}^{2}-7{a}^{2}\) | |
| Combine like terms. | \(-6{a}^{{}^{2}}+4{b}^{2}\) |
Remember, \(-6{a}^{2}\) and \(4{b}^{2}\) are not like terms. The variables are not the same.
Add and Subtract Polynomials
Adding and subtracting polynomials can be thought of as just adding and subtracting like terms. Look for like terms—those with the same variables with the same exponent. The Commutative Property allows us to rearrange the terms to put like terms together. It may also be helpful to underline, circle, or box like terms.
Example
Try it.
Find the sum: \((4{x}^{2}-5x+1)+(3{x}^{2}-8x-9).\)
Solution
| Identify like terms. | |
| Rearrange to get the like terms together. | |
| Combine like terms. |
Parentheses are grouping symbols. When we add polynomials as we did in , we can rewrite the expression without parentheses and then combine like terms. But when we subtract polynomials, we must be very careful with the signs.
Example
Try it.
Find the difference: \((7{u}^{2}-5u+3)-(4{u}^{2}-2).\)
Solution
| Distribute and identify like terms. | |
| Rearrange the terms. | |
| Combine like terms. |
Example
Try it.
Subtract: \(({m}^{2}-3m+8)\) from \((9{m}^{2}-7m+4).\)
Solution
| Distribute and identify like terms. | |
| Rearrange the terms. | |
| Combine like terms. |
Evaluate a Polynomial for a Given Value
In The Language of Algebra we evaluated expressions. Since polynomials are expressions, we'll follow the same procedures to evaluate polynomials—substitute the given value for the variable into the polynomial, and then simplify.
Example
Try it.
Evaluate \(3{x}^{2}-9x+7\) when
- ⓐ \(\ x=3\)
- ⓑ \(\ x=-1\)
Solution
| ⓐ \(x=3\) | |
| \(3{x}^{2}-9x+7\) | |
| Substitute 3 for \(x\) | \(3{(3)}^{2}-9(3)+7\) |
| Simplify the expression with the exponent. | \(3\cdot 9-9(3)+7\) |
| Multiply. | \(27-27+7\) |
| Simplify. | \(7\) |
| ⓑ \(x=-1\) | |
| \(3{x}^{2}-9x+7\) | |
| Substitute −1 for \(x\) | \(3{(-1)}^{2}-9(-1)+7\) |
| Simplify the expression with the exponent. | \(3\cdot 1-9(-1)+7\) |
| Multiply. | \(3+9+7\) |
| Simplify. | \(19\) |
Example
Try it.
The polynomial \(-16{t}^{2}+300\) gives the height of an object \(t\) seconds after it is dropped from a \(300\) foot tall bridge. Find the height after \(t=3\) seconds.
Solution
| Substitute 3 for \(t\) | |
| Simplify the expression with the exponent. | |
| Multiply. | |
| Simplify. |
Add and Subtract Polynomials
Identify Polynomials, Monomials, Binomials and Trinomials
In the following exercises, determine if each of the polynomials is a monomial, binomial, trinomial, or other polynomial.
Try it.
\(5x+2\)
Solution
binomial
Try it.
\({z}^{2}-5z-6\)
Try it.
\({a}^{2}+9a+18\)
Solution
trinomial
Try it.
\(-12{p}^{4}\)
Try it.
\({y}^{3}-8{y}^{2}+2y-16\)
Solution
polynomial
Try it.
\(10-9x\)
Try it.
\(23{y}^{2}\)
Solution
monomial
Try it.
\({m}^{4}+4{m}^{3}+6{m}^{2}+4m+1\)
Determine the Degree of Polynomials
In the following exercises, determine the degree of each polynomial.
Try it.
\(8{a}^{5}-2{a}^{3}+1\)
Solution
5
Try it.
\(5{c}^{3}+11{c}^{2}-c-8\)
Try it.
\(3x-12\)
Solution
1
Try it.
\(4y+17\)
Try it.
\(-13\)
Solution
0
Try it.
\(-22\)
Add and Subtract Monomials
In the following exercises, add or subtract the monomials.
Try it.
\({\text{6x}}^{2}+\ 9{x}^{2}\)
Solution
15x2
Try it.
\({\text{4y}}^{3}+\ 6{y}^{3}\)
Try it.
\(-12u\ +\ 4u\)
Solution
−8u
Try it.
\(-3m\ +\ 9m\)
Try it.
\(5a\ +\ 7b\)
Solution
5a + 7b
Try it.
\(8y\ +\ 6z\)
Try it.
Add: \(\ 4a\ ,\ -3b,\ -8a\)
Solution
−4a −3b
Try it.
Add: \(4x\ ,\ 3y\ ,\ -3x\)
Try it.
\(18x-2x\)
Solution
16x
Try it.
\(13a-3a\)
Try it.
Subtract \(5{x}^{6}\ \text{from}\ -12{x}^{6}\)
Solution
−17x6
Try it.
Subtract \(2{p}^{4}\ \text{from}\ -7{p}^{4}\)
Add and Subtract Polynomials
In the following exercises, add or subtract the polynomials.
Try it.
\((4{y}^{2}+10y+3)+(8{y}^{2}-6y+5)\)
Solution
12y2 + 4y + 8
Try it.
\((7{x}^{2}-9x+2)+(6{x}^{2}-4x+3)\)
Try it.
\(({x}^{2}+6x+8)+(-4{x}^{2}+11x-9)\)
Solution
−3x2 + 17x − 1
Try it.
\(({y}^{2}+9y+4)+(-2{y}^{2}-5y-1)\)
Try it.
\((3{a}^{2}+7)+({a}^{2}-7a-18)\)
Solution
4a2 − 7a − 11
Try it.
\(({p}^{2}-5p-11)+(3{p}^{2}+9)\)
Try it.
\((6{m}^{2}-9m-3)-(2{m}^{2}+m-5)\)
Solution
4m2 − 10m + 2
Try it.
\((3{n}^{2}-4n+1)-(4{n}^{2}-n-2)\)
Try it.
\(({z}^{2}+8z+9)-({z}^{2}-3z+1)\)
Solution
11z + 8
Try it.
\(({z}^{2}-7z+5)-({z}^{2}-8z+6)\)
Try it.
\((12{s}^{2}-15s)-(s-9)\)
Solution
12s2 − 16s + 9
Try it.
\((10{r}^{2}-20r)-(r-8)\)
Try it.
Find the sum of \((2{p}^{3}-8)\) and \(({p}^{2}+9p+18)\)
Solution
2p3 + p2 + 9p + 10
Try it.
Find the sum of \(({q}^{2}+4q+13)\) and \((7{q}^{3}-3)\)
Try it.
Subtract \((7{x}^{2}-4x+2)\) from \((8{x}^{2}-x+6)\)
Solution
x2 + 3x + 4
Try it.
Subtract \((5{x}^{2}-x+12)\) from \((9{x}^{2}-6x-20)\)
Try it.
Find the difference of \(({w}^{2}+w-42)\) and \(({w}^{2}-10w+24)\)
Solution
11w − 66
Try it.
Find the difference of \(({z}^{2}-3z-18)\) and \(({z}^{2}+5z-20)\)
Evaluate a Polynomial for a Given Value
In the following exercises, evaluate each polynomial for the given value.
Try it.
\(\text{Evaluate}\ 8{y}^{2}-3y+2\)
- ⓐ \(\ y=5\)
- ⓑ \(\ y=-2\)
- ⓒ \(\ y=0\)
Solution
- ⓐ 187
- ⓑ 40
- ⓒ 2
Try it.
\(\text{Evaluate}\ 5{y}^{2}-y-7\ \text{when:}\)
- ⓐ \(\ y=-4\\)
- ⓑ \(\ y=1\)
- ⓒ \(y=0\)
Try it.
\(\text{Evaluate}\ 4-36x\ \text{when:}\)
- ⓐ \(\ x=3\)
- ⓑ \(\ x=0\)
- ⓒ \(x=-1\)
Solution
- ⓐ −104
- ⓑ 4
- ⓒ 40
Try it.
\(\text{Evaluate}\ 16-36{x}^{2}\ \text{when:}\)
- ⓐ \(\ x=-1\\)
- ⓑ \(\ x=0\)
- ⓒ \(x=2\)
Try it.
A window washer drops a squeegee from a platform \(275\) feet high. The polynomial \(-16{t}^{2}+275\) gives the height of the squeegee \(t\) seconds after it was dropped. Find the height after \(t=4\) seconds.
Solution
19 feet
Try it.
A manufacturer of microwave ovens has found that the revenue received from selling microwaves at a cost of p dollars each is given by the polynomial \(-5{p}^{2}+350p.\) Find the revenue received when \(p=50\) dollars.
Condensed — the full section is in OpenStax Prealgebra 2e.
Practice (40)
Try each one on paper first. Reveal the answer to check; verified ones can be opened in the solver for every step.
-
Simplify: \(8x+3x.\)
If you missed this problem, review .উত্তর প্রকাশ করুন
\(11x\)
-
Subtract: \((5n+8)-(2n-1).\)
If you missed this problem, review .উত্তর প্রকাশ করুন
\(3n+9\)
-
Evaluate: \(4{y}^{2}\) when \(y=5\)
If you missed this problem, review .উত্তর প্রকাশ করুন
\(100\)
-
Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial:
- ⓐ \(\ 8{x}^{2}-7x-9\)
- ⓑ \(\ -5{a}^{4}\)
- ⓒ \(\ {x}^{4}-7{x}^{3}-6{x}^{2}+5x+2\)
- ⓓ \(\ 11-4{y}^{3}\)
- ⓔ \(\ n\)
উত্তর প্রকাশ করুন
Polynomial Number of terms Type ⓐ \(8{x}^{2}-7x-9\) 3 Trinomial ⓑ \(-5{a}^{4}\) 1 Monomial ⓒ \({x}^{4}-7{x}^{3}-6{x}^{2}+5x+2\) 5 Polynomial ⓓ \(11-4{y}^{3}\) 2 Binomial ⓔ \(n\) 1 Monomial -
Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial.
- ⓐ \(\ z\)
- ⓑ \(\ 2{x}^{3}-4{x}^{2}-x-8\)
- ⓒ \(\ 6{x}^{2}-4x+1\)
- ⓓ \(\ 9-4{y}^{2}\)
- ⓔ \(\ 3{x}^{7}\)
উত্তর প্রকাশ করুন
- ⓐ monomial
- ⓑ polynomial
- ⓒ trinomial
- ⓓ binomial
- ⓔ monomial
-
Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial.
- ⓐ \(\ {y}^{3}-8\)
- ⓑ \(\ 9{x}^{3}-5{x}^{2}-x\)
- ⓒ \(\ {x}^{4}-3{x}^{2}-4x-7\)
- ⓓ \(\ \text{-}{y}^{4}\)
- ⓔ \(\ w\)
উত্তর প্রকাশ করুন
- ⓐ binomial
- ⓑ trinomial
- ⓒ polynomial
- ⓓ monomial
- ⓒ monomial
-
Find the degree of the following polynomials:
- ⓐ \(\ 4x\)
- ⓑ \(\ 3{x}^{3}-5x+7\)
- ⓒ \(\ -11\)
- ⓓ \(\ -6{x}^{2}+9x-3\)
- ⓔ \(\ 8x+2\)
উত্তর প্রকাশ করুন
ⓐ \(4x\) The exponent of \(x\) is one. \(x={x}^{1}\) The degree is 1. ⓑ \(3{x}^{3}-5x+7\) The highest degree of all the terms is 3. The degree is 3 ⓒ \(-11\) The degree of a constant is 0. The degree is 0. ⓓ \(-6{x}^{2}+9x-3\) The highest degree of all the terms is 2. The degree is 2. ⓔ \(8x+2\) The highest degree of all the terms is 1. The degree is 1. -
Find the degree of the following polynomials:
- ⓐ \(\ -6y\)
- ⓑ \(\ 4x-1\)
- ⓒ \(\ 3{x}^{4}+4{x}^{2}-8\)
- ⓓ \(\ 2{y}^{2}+3y+9\)
- ⓔ \(\ -18\)
উত্তর প্রকাশ করুন
- ⓐ 1
- ⓑ 1
- ⓒ 4
- ⓓ 2
- ⓔ 0
-
Find the degree of the following polynomials:
- ⓐ \(\ 47\)
- ⓑ \(\ 2{x}^{2}-8x+2\)
- ⓒ \(\ {x}^{4}-16\)
- ⓓ \(\ {y}^{5}-5{y}^{3}+y\)
- ⓔ \(\ 9{a}^{3}\)
উত্তর প্রকাশ করুন
- ⓐ 0
- ⓑ 2
- ⓒ 4
- ⓓ 5
- ⓔ 3
-
Add: \(17{x}^{2}+6{x}^{2}.\)
উত্তর প্রকাশ করুন
\(17{x}^{2}+6{x}^{2}\) Combine like terms. \(23{x}^{2}\) -
Add: \(12{x}^{2}+5{x}^{2}.\)
উত্তর প্রকাশ করুন
17x2
-
Add: \(-11{y}^{2}+8{y}^{2}.\)
উত্তর প্রকাশ করুন
−3y2
-
Subtract: \(11n-(-8n).\)
উত্তর প্রকাশ করুন
\(11n-(-8n)\) Combine like terms. \(19n\) -
Subtract: \(9n-(-5n).\)
উত্তর প্রকাশ করুন
14n
-
Subtract: \(-7{a}^{3}-(-5{a}^{3}).\)
উত্তর প্রকাশ করুন
−2a3
-
Simplify: \({a}^{2}+4{b}^{2}-7{a}^{2}.\)
উত্তর প্রকাশ করুন
\({a}^{2}+4{b}^{2}-7{a}^{2}\) Combine like terms. \(-6{a}^{{}^{2}}+4{b}^{2}\) Remember, \(-6{a}^{2}\) and \(4{b}^{2}\) are not like terms. The variables are not the same.
-
Add: \(3{x}^{2}+3{y}^{2}-5{x}^{2}.\)
উত্তর প্রকাশ করুন
−2x2 + 3y2
-
Add: \(2{a}^{2}+{b}^{2}-4{a}^{2}.\)
উত্তর প্রকাশ করুন
−2a2 + b2
-
Find the sum: \((4{x}^{2}-5x+1)+(3{x}^{2}-8x-9).\)
উত্তর প্রকাশ করুন
Identify like terms. Rearrange to get the like terms together. Combine like terms. -
Find the sum: \((3{x}^{2}-2x+8)+({x}^{2}-6x+2).\)
উত্তর প্রকাশ করুন
4x2 − 8x + 10
-
Find the sum: \((7{y}^{2}+4y-6)+(4{y}^{2}+5y+1).\)
উত্তর প্রকাশ করুন
11y2 + 9y − 5
-
Find the difference: \((7{u}^{2}-5u+3)-(4{u}^{2}-2).\)
উত্তর প্রকাশ করুন
Distribute and identify like terms. Rearrange the terms. Combine like terms. -
Find the difference: \((6{y}^{2}+3y-1)-(3{y}^{2}-4).\)
উত্তর প্রকাশ করুন
3y2 + 3y + 3
-
Find the difference: \((8{u}^{2}-7u-2)-(5{u}^{2}-6u-4).\)
উত্তর প্রকাশ করুন
3u2 − u + 2
-
Subtract: \(({m}^{2}-3m+8)\) from \((9{m}^{2}-7m+4).\)
উত্তর প্রকাশ করুন
Distribute and identify like terms. Rearrange the terms. Combine like terms. -
Subtract: \((4{n}^{2}-7n-3)\) from \((8{n}^{2}+5n-3).\)
উত্তর প্রকাশ করুন
4n2 + 12n
-
Subtract: \(({a}^{2}-4a-9)\) from \((6{a}^{2}+4a-1).\)
উত্তর প্রকাশ করুন
5a2 + 8a + 8
-
Evaluate \(3{x}^{2}-9x+7\) when
- ⓐ \(\ x=3\)
- ⓑ \(\ x=-1\)
উত্তর প্রকাশ করুন
ⓐ \(x=3\) \(3{x}^{2}-9x+7\) Substitute 3 for \(x\) \(3{(3)}^{2}-9(3)+7\) Simplify the expression with the exponent. \(3\cdot 9-9(3)+7\) Multiply. \(27-27+7\) Simplify. \(7\) ⓑ \(x=-1\) \(3{x}^{2}-9x+7\) Substitute −1 for \(x\) \(3{(-1)}^{2}-9(-1)+7\) Simplify the expression with the exponent. \(3\cdot 1-9(-1)+7\) Multiply. \(3+9+7\) Simplify. \(19\) -
Evaluate: \(2{x}^{2}+4x-3\) when
- ⓐ \(\ x=2\)
- ⓑ \(\ x=-3\)
উত্তর প্রকাশ করুন
- ⓐ 13
- ⓑ 3
-
Evaluate: \(7{y}^{2}-y-2\) when
- ⓐ \(\ y=-4\)
- ⓑ \(\ y=0\)
উত্তর প্রকাশ করুন
- ⓐ 114
- ⓑ −2
-
The polynomial \(-16{t}^{2}+300\) gives the height of an object \(t\) seconds after it is dropped from a \(300\) foot tall bridge. Find the height after \(t=3\) seconds.
উত্তর প্রকাশ করুন
Substitute 3 for \(t\) Simplify the expression with the exponent. Multiply. Simplify. -
The polynomial \(-8{t}^{2}+24t+4\) gives the height, in feet, of a ball \(t\) seconds after it is tossed into the air, from an initial height of \(4\) feet. Find the height after \(t=3\) seconds.
উত্তর প্রকাশ করুন
4 feet
-
The polynomial \(-8{t}^{2}+24t+4\) gives the height, in feet, of a ball \(x\) seconds after it is tossed into the air, from an initial height of \(4\) feet. Find the height after \(t=2\) seconds.
উত্তর প্রকাশ করুন
20 feet
-
\({z}^{2}-5z-6\)
-
\({a}^{2}+9a+18\)
উত্তর প্রকাশ করুন
trinomial
-
\(-12{p}^{4}\)
-
\({y}^{3}-8{y}^{2}+2y-16\)
উত্তর প্রকাশ করুন
polynomial
-
\(23{y}^{2}\)
উত্তর প্রকাশ করুন
monomial
-
\({m}^{4}+4{m}^{3}+6{m}^{2}+4m+1\)
-
\(8{a}^{5}-2{a}^{3}+1\)
উত্তর প্রকাশ করুন
5
Symbols used here
Both signs at once: x = 3 ± 2 means 5 and 1.
The two sides are different.
Inequalities that allow equality; < and > exclude it.
Equal to the precision shown, not exactly.
The non-negative number whose square (n-th power) is x.
What is left after dividing a by n.
Per hundred: 15% = 15/100.
a for every b; a divided by b.
How to: Add and Subtract Polynomials
- Identify polynomials, monomials, binomials, and trinomials
- Determine the degree of polynomials
- Add and subtract monomials
- Add and subtract polynomials
- Evaluate a polynomial for a given value
Questions people ask
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.
নিজের চেষ্টা করো
Parts of this page are adapted from OpenStax Prealgebra 2e (CC BY-NC-SA 4.0). Condensed and re-explained here; errors are ours.