Answer
7 inches by 16 inches
Work Step by Step
length = x, width = w
$x=9+w$
$a=w*x$
$a = 112$
$112 = w*x$
$112 = w * (9+w)$
$w^2+9w-112=0$
$w^2+16w-7w-112=0$
$w(w+16)-7(w-16)=0$
$(w+16)(w-7)=0$
$w+16=0$
$w=-16$ (not a solution since we can't have a negative length)
$w-7=0$
$w=7$
$x=9+w$
$x=9+7$
$x=16$
