tentukan hp dari x+2y=7 dan 2x+3y=4

sub.pers I ke pers II.
x = 7-2y ke 2(7-2y)+3y
=14-4y+3y
= 14-y
y=14,,
pers I ,,x + 2y = 7
x +2(14)=7
x + 28 = 7
x = 7-28
x = -21,,,HP x=-21 dan y= 14