penyelesaian dari 1/4x-2/3y=5 dan 1/2x+ 2/3y=-2 adalah x=p dan y=q Nilai p-4q adalah?

1/4x-2/3y=5
1/2x+2/3y=-2
___________ +
1/4x + 1/2 x = 3
3/4 x = 3
x = 3 × 4/3
x = 4

1/4x - 2/3y = 5
1/4(4) - 2/3y = 5
1 - 2/3y = 5
- 2/3 y = 5-1
-2/3y = 4
-y = 4×3/2
-y = 6
y = -6

x = p, y= q
p - 4q = 4 - (4×-6)
= 4 - (-24)
= 4 + 24
= 28