Page 607 - Algebra 1

L E S S O N Adding and Subtracting Rational Expressions 90
Warm Up
1. Vocabulary One of two or more numbers or expressions that are
(2)
multiplied to get a product is a(n) of the product.
2. Simplify _7 + _5 . (10) 12 18
4. Multiply: 6r2(3r - 8). (58)
3. Simplify 3x4y + 7y2 - 4x4y. (18)
5. Multiply: (x - 7)(x - 3). (58)
NewConcepts Addingandsubtractingrationalexpressionsfollowthesamerulesasadding and subtracting fractions. If the denominators are the same, add the numerators
and keep the common denominator. If the denominators are not the same, use the least common multiple of the denominators as the common denominator.
Adding and Subtracting with Like Denominators
Add or subtract. Simplify your answers. _2 _2
Example
1
a. 2x + 3x 20x 20x
SOLUTION
2x + 3x _2 _2
20x 20x _2
= 5x 20x
Add the numerators. Keep the denominator. Simplify.
Subtract the numerators. Keep the denominator. Distribute-1.
Combine like terms.
Factor and divide out common factors.
= _x 4
b. 3a-2-a-6 __
a+2 a+2 SOLUTION
3a-2 - a-6 __
a+2 a+2
= 3a - 2 - (a - 6)
Online Connection www.SaxonMathResources.com
_a+2 = 2a + 4
_a + 2
= 2(a + 2) a+2
= 2
__ a+2
Caution
Not enclosing the numerator of the subtrahend in parentheses may result in sign errors.
= 3a-2-a+6 __
592 Saxon Algebra 1