CPM Homework Help : PC Problem 5-28

Rewrite each of the following expressions as a single fraction without negative exponents.

$\frac { x ^ { - 2 } + y ^ { 2 } } { x ^ { 2 } - y ^ { - 2 } }$
Hint (b):
What GIANT ONE should you multiply this fraction by?
Answer (b:)
$\frac{x^{2}y^{2}}{x^{2}y^{2}}$

$\frac { x ^ { - 4 } y ^ { - 2 } + x ^ { - 3 } y ^ { - 1 } } { x ^ { - 1 } - x ^ { - 3 } }$
Hint (c):
What GIANT ONE should you multiply this fraction by?
Answer (c):
$\frac{x^{4}y^{2}}{x^{4}y^{2}}$