1)2p-q=4 P-3q=2 2)5x-y=10 X+5y=15

1.
2p - q = 4 ... (1)
p - 3q = 2 » p = 2 + 3q ... (2)

substitusi (2) ke (1)
2(2 + 3q) - q = 4
4 + 6q - q = 4
q = 0

substitusi q = 0 ke (1)
2p - q = 4
2p = 4
p = 2


2.
5x - y = 10 » y = 5x - 10 ...(1)
x + 5y = 15 ...(2)

substitusi (1) ke (2)
x + 5(5x - 10) = 15
x + 25x - 50 = 15
26x = 65
x = 5/2

substitusi x = 5/2 ke (1)
y = 5(5/2) - 10
y = 25/2 - 20/2
y = 5/2