m81334 Add and Subtract Polynomials By the end of this section, you will be able to: 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 7ebb5485-ff7f-4df5-8028-12ab4eabdb82 Before you get started, take this readiness quiz. Simplify: 8x+3x. If you missed this problem, review . 11x Subtract: (5n+8)−(2n−1). If you missed this problem, review . 3n+9 Evaluate: 4y2 when y=5 If you missed this problem, review . 100

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 axm, 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. polynomial—A monomial, or two or more monomials, combined by addition or subtractionmonomial—A polynomial with exactly one term binomial— A polynomial with exactly two termstrinomial—A polynomial with exactly three terms Notice the roots: poly- means many mono- means one bi- means two tri- means three Here are some examples of polynomials: Polynomial b+1 4y2−7y+2 5x5−4x4+x3+8x2−9x+1 Monomial 5 4b2 −9x3 Binomial 3a−7 y2−9 17x3+14x2 Trinomial x2−5x+6 4y2−7y+2 5a4−3a3+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’. Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial: ⓐ 8x2−7x−9ⓑ −5a4ⓒ x4−7x3−6x2+5x+2ⓓ 11−4y3ⓔ n Polynomial Number of terms Type ⓐ 8x2−7x−9 3 Trinomial ⓑ −5a4 1 Monomial ⓒ x4−7x3−6x2+5x+2 5 Polynomial ⓓ 11−4y3 2 Binomial ⓔ n 1 Monomial Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial. ⓐ zⓑ 2x3−4x2−x−8ⓒ 6x2−4x+1ⓓ 9−4y2ⓔ 3x7 ⓐ monomialⓑ polynomialⓒ trinomialⓓ binomialⓔ monomial Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial. ⓐ y3−8ⓑ 9x3−5x2−xⓒ x4−3x2−4x−7ⓓ −y4ⓔ w ⓐ binomialⓑ trinomialⓒ polynomialⓓ monomialⓒ monomial

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.The degree of a term is the exponent of its variable. The degree of a constant is 0.The degree of a polynomial is the highest degree of all its terms. 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. Find the degree of the following polynomials: ⓐ 4xⓑ 3x3−5x+7ⓒ −11ⓓ −6x2+9x−3ⓔ 8x+2 ⓐ 4x The exponent of x is one. x=x1 The degree is 1. ⓑ 3x3−5x+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. ⓓ −6x2+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ⓒ 3x4+4x2−8ⓓ 2y2+3y+9ⓔ −18 ⓐ 1ⓑ 1ⓒ 4ⓓ 2ⓔ 0 Find the degree of the following polynomials: ⓐ 47ⓑ 2x2−8x+2ⓒ x4−16ⓓ y5−5y3+yⓔ 9a3 ⓐ 0ⓑ 2ⓒ 4ⓓ 5ⓔ 3 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.

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. Add: 17x2+6x2. 17x2+6x2 Combine like terms. 23x2 Add: 12x2+5x2. 17x² Add: −11y2+8y2. −3y² Subtract: 11n−(−8n). 11n−(−8n) Combine like terms. 19n Subtract: 9n−(−5n). 14n Subtract: −7a3−(−5a3). −2a³ Simplify: a2+4b2−7a2. a2+4b2−7a2 Combine like terms. −6a2+4b2 Remember, −6a2 and 4b2 are not like terms. The variables are not the same. Add: 3x2+3y2−5x2. −2x² + 3y² Add: 2a2+b2−4a2. −2a² + b²

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. Find the sum: (4x2−5x+1)+(3x2−8x−9). Identify like terms. Rearrange to get the like terms together. Combine like terms. Find the sum: (3x2−2x+8)+(x2−6x+2). 4x² − 8x + 10 Find the sum: (7y2+4y−6)+(4y2+5y+1). 11y² + 9y − 5 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. Find the difference: (7u2−5u+3)−(4u2−2). Distribute and identify like terms. Rearrange the terms. Combine like terms. Find the difference: (6y2+3y−1)−(3y2−4). 3y² + 3y + 3 Find the difference: (8u2−7u−2)−(5u2−6u−4). 3u² − u + 2 Subtract: (m2−3m+8) from (9m2−7m+4). Distribute and identify like terms. Rearrange the terms. Combine like terms. Subtract: (4n2−7n−3) from (8n2+5n−3). 4n² + 12n Subtract: (a2−4a−9) from (6a2+4a−1). 5a² + 8a + 8

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. Evaluate 3x2−9x+7 when ⓐ x=3ⓑ x=−1 ⓐ x=3 3x2−9x+7 Substitute 3 for x 3(3)2−9(3)+7 Simplify the expression with the exponent. 3·9−9(3)+7 Multiply. 27−27+7 Simplify. 7 ⓑ x=−1 3x2−9x+7 Substitute −1 for x 3(−1)2−9(−1)+7 Simplify the expression with the exponent. 3·1−9(−1)+7 Multiply. 3+9+7 Simplify. 19 Evaluate: 2x2+4x−3 when ⓐ x=2ⓑ x=−3 ⓐ 13ⓑ 3 Evaluate: 7y2−y−2 when ⓐ y=−4ⓑ y=0 ⓐ 114ⓑ −2 The polynomial −16t2+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. Substitute 3 for t Simplify the expression with the exponent. Multiply. Simplify. The polynomial −8t2+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. 4 feet The polynomial −8t2+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. 20 feet Adding Polynomials Subtracting 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. 5x+2 binomial z2−5z−6 a2+9a+18 trinomial −12p4 y3−8y2+2y−16 polynomial 10−9x 23y2 monomial m4+4m3+6m2+4m+1 Determine the Degree of Polynomials In the following exercises, determine the degree of each polynomial. 8a5−2a3+1 5 5c3+11c2−c−8 3x−12 1 4y+17 −13 0 −22 Add and Subtract Monomials In the following exercises, add or subtract the monomials. 6x2+9x2 15x² 4y3+6y3 −12u+4u −8u −3m+9m 5a+7b 5a + 7b 8y+6z Add: 4a,−3b,−8a −4a −3b Add: 4x,3y,−3x 18x−2x 16x 13a−3a Subtract 5x6from−12x6 −17x⁶ Subtract 2p4from−7p4 Add and Subtract Polynomials In the following exercises, add or subtract the polynomials. (4y2+10y+3)+(8y2−6y+5) 12y² + 4y + 8 (7x2−9x+2)+(6x2−4x+3) (x2+6x+8)+(−4x2+11x−9) −3x² + 17x − 1 (y2+9y+4)+(−2y2−5y−1) (3a2+7)+(a2−7a−18) 4a² − 7a − 11 (p2−5p−11)+(3p2+9) (6m2−9m−3)−(2m2+m−5) 4m² − 10m + 2 (3n2−4n+1)−(4n2−n−2) (z2+8z+9)−(z2−3z+1) 11z + 8 (z2−7z+5)−(z2−8z+6) (12s2−15s)−(s−9) 12s² − 16s + 9 (10r2−20r)−(r−8) Find the sum of (2p3−8) and (p2+9p+18) 2p³ + p² + 9p + 10 Find the sum of (q2+4q+13) and (7q3−3) Subtract (7x2−4x+2) from (8x2−x+6) x² + 3x + 4 Subtract (5x2−x+12) from (9x2−6x−20) Find the difference of (w2+w−42) and (w2−10w+24) 11w − 66 Find the difference of (z2−3z−18) and (z2+5z−20) Evaluate a Polynomial for a Given Value In the following exercises, evaluate each polynomial for the given value. Evaluate8y2−3y+2ⓐ y=5ⓑ y=−2ⓒ y=0 ⓐ 187ⓑ 40ⓒ 2 Evaluate5y2−y−7when:ⓐ y=−4ⓑ y=1ⓒ y=0 Evaluate4−36xwhen:ⓐ x=3ⓑ x=0ⓒ x=−1 ⓐ −104ⓑ 4ⓒ 40 Evaluate16−36x2when:ⓐ x=−1ⓑ x=0ⓒ x=2 A window washer drops a squeegee from a platform 275 feet high. The polynomial −16t2+275 gives the height of the squeegee t seconds after it was dropped. Find the height after t=4 seconds. 19 feet 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 −5p2+350p. Find the revenue received when p=50 dollars.

Fuel Efficiency The fuel efficiency (in miles per gallon) of a bus going at a speed of x miles per hour is given by the polynomial −1160x2+12x. Find the fuel efficiency when x=40mph. 10 mpg Stopping Distance The number of feet it takes for a car traveling at x miles per hour to stop on dry, level concrete is given by the polynomial 0.06x2+1.1x. Find the stopping distance when x=60mph.

Using your own words, explain the difference between a monomial, a binomial, and a trinomial. Answers will vary. Eloise thinks the sum 5x2+3x4 is 8x6. What is wrong with her reasoning?

ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

ⓑ If most of your checks were: …confidently. Congratulations! You have achieved the objectives in this section. Reflect on the study skills you used so that you can continue to use them. What did you do to become confident of your ability to do these things? Be specific. …with some help. This must be addressed quickly because topics you do not master become potholes in your road to success. In math, every topic builds upon previous work. It is important to make sure you have a strong foundation before you move on. Whom can you ask for help? Your fellow classmates and instructor are good resources. Is there a place on campus where math tutors are available? Can your study skills be improved? …no—I don’t get it! This is a warning sign and you must not ignore it. You should get help right away or you will quickly be overwhelmed. See your instructor as soon as you can to discuss your situation. Together you can come up with a plan to get you the help you need.

binomial A binomial is a polynomial with exactly two terms. degree of a constant The degree of a constant is 0. degree of a polynomial The degree of a polynomial is the highest degree of all its terms. degree of a term The degree of a term of a polynomial is the exponent of its variable. monomial A term of the form axm, where a is a constant and m is a whole number, is called a monomial. polynomial A polynomial is a monomial, or two or more monomials, combined by addition or subtraction. trinomial A trinomial is a polynomial with exactly three terms.