Solve the linear system graphically

Question

(Dont graph it just solve it)
x+ 2y = 8
3x+ 4y = 20

Answer 1

double the first:
2x + 4y = 16
subtract from the 2nd

x = 4
back into the 1st:
4 + 2y = 8
2y = 4
y = 2

x = 4, y = 2