Y = -8x + 56
2y= -2x + 56 (you want to get rid of one variable then solve for it then solve for the other)
-2(y=-8x+56)
2y=-2x+56
-2y=16x-112
2y=-2x+56 (see how multi the first equation by -2 gets the y's to cancel so can solve for x. Now sum up the equations)
0= 14x-56
x= 4
now plug x=4 into any original equation Y=-8x+56
Y = -8(4)+56
Y=24
hope this helps