You have the folloiwng system of equations:
4x + 8y = 20
-4x + 2y = -30
In order to solve the previous system, proceed as follow:
Sum the equations and solve for y:
4x + 8y = 20
-4x + 2y = -30
10y = -10
Divide by 10 both sides
y = -10/10
y = -1
Now, replace the previous value of y into the any of the equations of the system, for instance, into the first equation and solve for x:
4x + 8y = 20
4x + 8(-1) = 20
4x - 8 = 20
add 8 boht sides, simlplify and divide by 4 both sides:
4x = 20 + 8
4x = 28
x = 28/4
x = 7
Hence, the solution of the given system of equations is given by:
x = 7
y = -1