so you subsitute y=2/3x-4 for y in 2x+y=4 so 2x+(2/3x-4)=4 2x+2/3x-4=4 add like terms 2 and 2/3x-4=4 add 4 to both sidees 2 and 2/3x=8 2 and 2/3=6/3+2/3=8/3 8/3x=8 multiply both sides by 3/8 (makes 8/3=24/24=1/1=1) x=(3*8)/8 simplify x=3 subtitute x=3 into y=2/3x-4 y=2/3(3)-4 y=(6/3)-4 y=2-4 y=-2
