Answer :

(24-y)/4=4
24-y     =4*4
24-y     =16
-y        =16-24
-y        =-8
y         =8
[tex]\frac{24-y}{4}=4\\\\\frac{24}{4}-\frac{y}{4}=4\\\\6-\frac{y}{4}=4\ \ \ \ \ |subtract\ 6\ from\ both\ sides\\\\-\frac{y}{4}=-2\ \ \ \ \ |multiply\ both\ sides\ by\ (-4)\\\\\boxed{y=8}[/tex]