Some students prefer Method 1 for problems like Example 2,which is the
quotient of two fractions. They will use Method 2 for problems like Examples 1,
3, 4, and 5,which have sums or differences in the numerators, or denominators,
or both.
Deciding on a Method and Simplifying Complex Fractions
Simplify each complex fraction.
(a)
Distributive property
Fundamental property
Distributive property
= Combine like terms.
3 y+ 2
y+ 8
=
y+ 2 + 2 y
4 y+ 8 - 3 y
=
11 y+ 22 + 2 y
41 y+ 22 - 3 y
a
1
y
b y 1 y+ 22 +a
2
y+ 2
b y 1 y+ 22
a
4
y
b y 1 y+ 22 - a
3
y+ 2
b y 1 y+ 22
=
a
1
y
+
2
y+ 2
b#y 1 y+ 22
a
4
y
3
y+ 2
b#y 1 y+ 22
=
1
y
+
2
y+ 2
4
y
3
y+ 2
EXAMPLE 6
452 CHAPTER 7 Rational Expressions and Applications
Be careful not to use as the LCD. Because yappears in two denominators, it
must be a factor in the LCD.
y+ 2
There are sums and differences
in the numerator and denominator.
Use Method 2.
Multiply numerator and
denominator by the LCD,
y 1 y+ 22.
(b)
Distributive property
Factor.
= Divide out the common factor.
x+ 1
x- 2
=
1 x- 321 x+ 12
1 x- 321 x- 22
=
x^2 - 2 x- 3
x^2 - 5 x+ 6
a 1 -
2
x
- 3
x^2
bx^2
a 1 -
5
x
+
6
x^2
bx^2
=
1 -
2
x
- 3
x^2
1 -
5
x
+
6
x^2
There are sums and differences
in the numerator and denominator.
Use Method 2.
Multiply numerator and
denominator by the LCD, x^2.
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