9.1
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VocabularyMonomial – Polynomial with 1 term.Binomial – Polynomial with 2 terms.Trinomial – Polynomial with 3 terms.
VocabularyMonomial – a number, a variable with a
positive integer exponent, or the product of a number and one or more variables with positive integer exponents.
Degree of a monomial – sum of the exponents of the variables in the monomial
VocabularyPolynomial – a monomial or a sum of
monomials, each called a term of the polynomial.
Degree of a polynomial – the greatest degree of its terms.
Leading coefficient – the coefficient of the highest degree term.
Rewrite a polynomial
Write so that the exponents decrease from left to right. Identify the degree and leading coefficient of the polynomial.
Example 1
315x +x3–
SOLUTION
The polynomial can be written as . The table shows the degree of each term. The greatest degree is 3, so the degree of the polynomial is 3, and the leading coefficient is .
15x+x3– 3+
1–
Term
Degree
15x 3
3 1 0
x3–
Identify and classify polynomials
Tell whether the expression is a polynomial. If it is a polynomial, find its degree and classify it by the number of its terms. Otherwise, tell why it is not a polynomial.
Example 2
Expression Is it a polynomial? Classify by degree and number of terms
9 Yes 0 degree monomiala.
Yes 2nd degree trinomialb. x2x2 + 5–
No; variable exponentc.
No; negative exponentd.
6n4 8n–
Yes 5th degree binomiale. 4b4c7bc3 +
n–2 3–
Adding & Subtracting PolynomialsTo add polynomials, combine like terms.
To subtract a polynomial, add its opposite
To find the opposite of a polynomial, multiply
each of its terms by -1
Add and subtract monomials
Find the sum or difference.
Example 3
a. 7b2+3b2–
5xy2xy –b.
4b2= Combine like terms.
+= 2xy 5xy–( ) Rewrite as a sum.
= 3xy– Combine like terms.
Add polynomials
Find the sum
Example 4
x3x2 + 6–( ) 4x+x2 10+( ).+
= x23x2 +( ) + 4x+x( ) 10+ )+ ( 6–
= 5x+4x2 4+
x3x2 + 6–( ) 4x+x2 10+( )+
SOLUTION
Group like terms and simplify.
Multiple Choice PracticeExample 5
3x4x2 5+( )– – x3x2 8( )– =
4xx2 3– – 2xx2 3– –
4xx2 13– +2xx2 13– +
= 3x4x2 5+– – x3x2 8++
= 3x24x2( – ) 3x x+ )(+ – ( )8+5+
= 2xx2 13– +
–
SOLUTION
3x4x2 5+( )– – x3x2 8( )– –
Multiple Choice PracticeExample 5
ANSWER The correct answer is C.