## Algebra: A Combined Approach (4th Edition)

$\dfrac{y-9}{9-y}=-1$
$\dfrac{y-9}{9-y}$ Rewrite the expression by changing the sign of the denominator. To do so, also change the sign of the fraction. Then, simplify: $\dfrac{y-9}{9-y}=-\dfrac{y-9}{y-9}=-1$