Pre-Algebra Demystified

EXAMPLE

Subtract (2a
3b
c)
(5a
6b
c).

SOLUTION

ð2a
3b
cÞ
ð5a
6b
cÞ¼2a
3b
c
5aþ6bþc

¼ð2a
5aÞþð
3bþ6bÞþð
cþcÞ

¼
3aþ3b

PRACTICE

Subtract:

1. (6x
   3)
   (xþ8)


2. (2x^2 þ5x
   3)
   (4x^2 þ5xþ5)


3. (3a
   2bþ6)
   (
   5a
   3bþ4)


4. (13r
   2s)
   (15sþ3r)


5. (y^2 þ6y
   10)
   (5þ8y
   y^2 )

ANSWERS

1. 5x
   11


2. 
   2x^2
   8


3. 8aþbþ 2


4. 10r
   17s


5. 2y^2
   2y
   15

Multiplication of Monomials

When two variables with the same base are multiplied, the exponents of the

variables are added to get the product. For example,

x^3 x^4 ¼xxxxxxx¼x^3 þ^4 ¼x^7

In general,

xmxn¼xmþn

EXAMPLE

Multiply y^5 y^6.

236 CHAPTER 12 Monomials and Polynomials