Beginning Algebra, 11th Edition

Using the data, we developed the quadratic equation

to model eBay revenues yin year x, where represents 2002, represents 2003,

and so on.

(a)Use the model to find annual revenue for eBay in 2005 and 2007, to the nearest

hundredth. How do the results compare with the actual data in the table?

(b)Use the model to estimate annual revenue for eBay in 2009, to the nearest hundredth.

(c)Actual revenue for eBay in 2009 was $8.73 billion. How does the result from part (b)

compare with the actual revenue in 2009?

(d)Should the quadratic equation be used to estimate eBay revenue for years after 2007?

Explain.

x= 0 x= 1

y=0.089x^2 +0.841x+1.224

410 CHAPTER 6 Factoring and Applications

Write each fraction in lowest terms. See Section 1.1.

- 35

- 21

48

- 27

- 26

156

50

72

PREVIEW EXERCISES

6.1

factor

factored form

common factor

greatest common

factor (GCF)

6.2

prime polynomial

6.4

perfect square

perfect square trinomial

6.5

quadratic equation

standard form

double solution

6.6

hypotenuse

legs

KEY TERMS

1. Factoringis
   A.a method of multiplying polynomials
   B.the process of writing a polynomial
   as a product
   C.the answer in a multiplication problem
   D.a way to add the terms of a polynomial.
   2.A polynomial is in factored formwhen
   A.it is prime
   B.it is written as a sum
   C.the squared term has a coefficient of 1
   D.it is written as a product.

3.A perfect square trinomialis a trinomial

A.that can be factored as the square of

a binomial

B.that cannot be factored

C.that is multiplied by a binomial

D.all of whose terms are perfect squares.

4.A quadratic equationis an equation

that can be written in the form

A.

B.ax^2 +bx+c= 0 1 aZ 02

y=mx+b

C.

D..

5.A hypotenuseis

A.either of the two shorter sides

of a triangle

B.the shortest side of a triangle

C.the side opposite the right

angle in a triangle

D.the longest side in any triangle.

x=k

Ax+By=C

TEST YOUR WORD POWER

See how well you have learned the vocabulary in this chapter.

ANSWERS

SUMMARY

CHAPTER 6

1.B; Example: 2.D; Example:The factored form of is 3.A; Example:

is a perfect square trinomial. Its factored form is 4.B; Examples:

5.C; Example:In FIGURE 3of Section 6.6,the hypotenuse is the side labeled x+2.

a^2 + 2 a+ 1 1 a+ 122. y^2 - 3 y+ 2 =0, x^2 - 9 =0, 2 m^2 = 6 m+ 8

x^2 - 5 x-14 factors as 1 x- 721 x+ 22. x^2 - 5 x- 14 1 x- 721 x+ 22.

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