Question

X + y = 4 x - 3y = -4

Answer 1

{X + y = 4
{x - 3y = -4 (-1)

{X + y = 4
{-x+ 3y =4

0+4y=8
4y=8
y=8/4
y=2

x+y=4
x+2=4
x=4-2
x=2