Answer
$\dfrac{49-y^{2}}{y-7}=-y-7$
Work Step by Step
$\dfrac{49-y^{2}}{y-7}$
Factor the numerator:
$\dfrac{49-y^{2}}{y-7}=\dfrac{(7-y)(7+y)}{y-7}=...$
Change the sign of the denominator. To do so, also change the sign of the fraction. After that, simplify:
$...=-\dfrac{(7-y)(7+y)}{7-y}=-(7+y)=-y-7$
