x-3y=7 dan 4x+2y=18 sustitusi

x - 3y = 7
x = 3y + 7

4x + 2y = 18
4 (3y + 7) + 2y = 18
12y + 28 + 2y = 18
14y = 18 - 28
14y = -10
y = -10/14

x = 3y + 7
x = 3 (-10/14) + 7
x = -30/14 + 7
x = -15/7 + 7
x = 34/7