Pre-Algebra Demystified

SOLUTION

ðxþ 2 Þðx^2 þ5x
 6 Þ¼ðxþ 2 Þx^2 þðxþ 2 Þ5xþðxþ 2 Þð
 6 Þ

¼xx^2 þ 2 x^2 þx5xþ 2 5xþxð
 6 Þþ 2 ð
 6 Þ

¼x^3 þ2x^2 þ5x^2 þ10x
6x
 12

¼x^3 þ7x^2 þ4x
 12

Multiplication of polynomials can be performed vertically. The process is

similar to multiplying whole numbers.

EXAMPLE

Multiply (xþ2)(x^2 þ5x
6) vertically.

SOLUTION

x^2 þ 5x
 6

xþ 2

x^3 þ5x^2 
 6x Multiply the top by x

2x^2 þ10x
12 Multiply the top by 2

x^3 þ7x^2 þ 4x
12 Add like terms

EXAMPLE

Multiply (x^2 þ3x
8)(3x
5) vertically.

SOLUTION

x^2 þ 3x
 8

3x
 5

3x^3 þ9x^2 
24x


5x^2 
15xþ 40

3x^3 þ4x^2 
39xþ 40

Math Note: Be sure to place like terms under each other when

multiplying vertically.

PRACTICE

Multiply:

244 CHAPTER 12 Monomials and Polynomials