x+2y-4=0 dan x²-3x+y-4=0

x+2y-4=0
x=4-2y

sub
x²-3x+y-4=0
(4-2y)²-3(4-2y) +y-4=0
16 - 16y +4y² -12 + 6y+y-4=0
4y²-9y=0
y(4y-9)=0
y=0 atau 4y=9, y=9/4

sub
x=4-2y atau x = 4-2 x 9/4 = 4-9/2= 1/2
= 4