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7-6 Polynomials
A monomial is a number, a variable, or a product of numbers and variables with whole-number exponents. A monomial may be a constant or a single variable.
The degree of a monomial is the sum of the exponents of the variables. A constant has degree 0.
7-6 Polynomials
Additional Example 1: Finding the Degree of a Monomial
Find the degree of each monomial.
A. 4p4q3
The degree is 7.Add the exponents of the
variables: 4 + 3 = 7.
B. 7ed
The degree is 2.A variable written without an
exponent has an exponent of 1. 1+ 1 = 2.
C. 3
The degree is 0.There is no variable, but you
can write 3 as 3x0.
7-6 Polynomials
The terms of an expression are the parts being added or subtracted. See Lesson 1-7.
Remember!
7-6 PolynomialsCheck It Out! Example 1
Find the degree of each monomial.
a. 1.5k2m
The degree is 3.Add the exponents of the
variables: 2 + 1 = 3.
b. 4x
The degree is 1.Add the exponents of the
variables: 1 = 1.
c. 2c3
The degree is 3.Add the exponents of the
variables: 3 = 3.
7-6 Polynomials
Check up: p. 433 #’s 5,6
7-6 Polynomials
A polynomial is a monomial or a sum or difference of monomials. The degree of a polynomial is the degree of the term with the greatest degree.
7-6 Polynomials
The terms of a polynomial may be written in any order. However, polynomials that contain only one variable are usually written in standard form.
The standard form of a polynomial that contains one variable is written with the terms in order from greatest degree to least degree. When written in standard form, the coefficient of the first term is called the leading coefficient.
7-6 Polynomials
Write the polynomial in standard form. Then give the leading coefficient.
Additional Example 2A: Writing Polynomials in Standard Form
6x – 7x5 + 4x2 + 9
Find the degree of each term. Then arrange them in descending order:
6x – 7x5 + 4x2 + 9 –7x5 + 4x2 + 6x + 9
Degree 1 5 2 0 5 2 1 0
–7x5 + 4x2 + 6x + 9.The standard form is The leading coefficient is –7.
7-6 Polynomials
Write the polynomial in standard form. Then give the leading coefficient.
Additional Example 2B: Writing Polynomials in Standard Form
Find the degree of each term. Then arrange them in descending order:
y2 + y6 − 3y
y2 + y6 – 3y y6 + y2 – 3y
Degree 2 6 1 2 16
The standard form is The leading coefficient is 1.
y6 + y2 – 3y.
7-6 Polynomials
A variable written without a coefficient has a coefficient of 1.
Remember!
y5 = 1y5
7-6 PolynomialsCheck It Out! Example 2a
Write the polynomial in standard form. Then give the leading coefficient.
16 – 4x2 + x5 + 9x3
Find the degree of each term. Then arrange them in descending order:
16 – 4x2 + x5 + 9x3 x5 + 9x3 – 4x2 + 16
Degree 0 2 5 3 0235
The standard form is The leading coefficient is 1.
x5 + 9x3 – 4x2 + 16.
7-6 PolynomialsCheck It Out! Example 2b
Write the polynomial in standard form. Then give the leading coefficient.
Find the degree of each term. Then arrange them in descending order:
18y5 – 3y8 + 14y
18y5 – 3y8 + 14y –3y8 + 18y5 + 14y
Degree 5 8 1 8 5 1
The standard form is The leading coefficient is –3.
–3y8 + 18y5 + 14y.
7-6 Polynomials
Check up: p. 433 #’s 9,13
7-6 Polynomials
Some polynomials have special names based on their degree and the number of terms they have.
7-6 Polynomials
Classify each polynomial according to its degree and number of terms.
Additional Example 3: Classifying Polynomials
A. 5n3 + 4nDegree 3 Terms 2
5n3 + 4n is a cubic binomial.
B. –2xDegree 1 Terms 1
–2x is a linear monomial.
7-6 Polynomials
Classify each polynomial according to its degree and number of terms.
Check It Out! Example 3
a. x3 + x2 – x + 2Degree 3 Terms 4
x3 + x2 – x + 2 is a cubic polynomial.
b. 6
Degree 0 Terms 1 6 is a constant monomial.
c. –3y8 + 18y5 + 14yDegree 8 Terms 3
–3y8 + 18y5 + 14y is an 8th-degree trinomial.
7-6 Polynomials
Check up: p. 433 #’s16,18
7-6 Polynomials
A tourist accidentally drops her lip balm off the Golden Gate Bridge. The bridge is 220 feet from the water of the bay. The height of the lip balm is given by the polynomial –16t2 + 220, where t is time in seconds. How far above the water will the lip balm be after 3 seconds?
Additional Example 4: Application
Substitute the time for t to find the lip balm’s height.–16t2 + 220
–16(3)2 + 200 The time is 3 seconds.
–16(9) + 200Evaluate the polynomial by using
the order of operations.–144 + 20076
7-6 Polynomials
A tourist accidentally drops her lip balm off the Golden Gate Bridge. The bridge is 220 feet from the water of the bay. The height of the lip balm is given by the polynomial –16t2 + 220, where t is time in seconds. How far above the water will the lip balm be after 3 seconds?
Additional Example 5 Continued
After 3 seconds the lip balm will be 76 feet above the water.
7-6 PolynomialsCheck It Out! Example 4
What if…? Another firework with a 5-second fuse is launched from the same platform at a speed of 400 feet per second. Its height is given by –16t2 + 400t + 6. How high will this firework be when it explodes?Substitute the time for t to find the firework’s height.
–16t2 + 400t + 6
–16(5)2 + 400(5) + 6 The time is 5 seconds.
–16(25) + 400(5) + 6
–400 + 2000 + 6
–400 + 20061606
7-6 PolynomialsCheck It Out! Example 4 Continued
What if…? Another firework with a 5-second fuse is launched from the same platform at a speed of 400 feet per second. Its height is given by –16t2 +400t + 6. How high will this firework be when it explodes?
When the firework explodes, it will be 1606 feet above the ground.
7-6 Polynomials
Check up: p. 433 #’s 20
7-6 Polynomials
A root of a polynomial in one variable is a value of the variable for which the polynomial is equal to 0.
7-6 Polynomials
Additional Example 5: Identifying Roots of Polynomials
Tell whether each number is a root of 3x2 – 48.
A. 4
3x2 – 48
3(4)2 – 48
3(16) – 48
48 – 48
4 is a root of 3x2 – 48.
0
Substitute for x.
Simplify.
B. 0
3x2 – 48
3(0)2 – 48
3(0) – 48
0 – 48
–48 0 is not a root of 3x2 – 48.
7-6 Polynomials
Additional Example 5: Identifying Roots of Polynomials
Tell whether each number is a root of 3x2 – 48.
C. –4
3x2 – 48
3(–4)2 – 48
3(16) – 48
48 – 48
–4 is a root of 3x2 – 48. 0
Substitute for x.
Simplify.
7-6 PolynomialsCheck It Out! Example 5
Tell whether 1 is a root of 3x3 + x – 4.
3x3 + x – 4
3(1)3 + (1) – 4
3(1) + 1 – 4
3 + 1 – 4
1 is a root of 3x3 + x – 4. 0
Substitute for x.
Simplify.
7-6 Polynomials
Check up: p. 433 #’s 21, 23, 25