3(x-1) = 2x - y
3x-3 = 2x-y
3x-2x+y = 3
x + y = 3 ----> (1)
2(x+y) = 3+3y
2x + 2y = 3 + 3y
2x + 2y - 3y = 3
2x - y = 3 -----> (2)
make equation (1) and (2) together
x + y + 2x - y = 3+3
3x = 6
x = 2
now make x = 2 in equation (1)
x + y = 3
2 + y = 3
y = 3-2
y = 1
(x,y) = (2,1)
