Tentukan HP dari 7 x dikurangi 18 = -2 x
7x - 18 = -2x
7x - 18 + 18 = -2x + 18
7x = -2x + 18
7x + 2x = -2x + 2x + 18
9x = 18
9x/9 = 18/9
x = 2
HP = {2}
7x - 18 = -2x
7x - 18 + 18 = -2x + 18
7x = -2x + 18
7x + 2x = -2x + 2x + 18
9x = 18
9x/9 = 18/9
x = 2
HP = {2}