Tlong bantuin caranya yang no.9 &,12 ??

3x+3y=3 | x2 | 6x+6y=6
2x-4y=14 | x3 | 6x-12y=42
____________________ –
18y=-36
Y=-36/18= -2
Subsitusi y=-2
3x +3(-2)=3
3x + (-6) =3
3x -6 = 3
3x =3+6
X = 9/3 = 3

Subsitusi x = 3 dan y = -2
4x-3y = 4(3)-3(-2)=12 – (-6) = 12+6=18

9) 24/18 x 60 = 80 pasang (C)
12) ERROR (alias nggak tau)