Tolong dijawab ya

Misalkan persamaan (1) = 2x – 3y = -17 dan persamaan (2) = 3x + 2y = -6.
(1) 2x – 3y + 17 = 0
(2) 3x + 2y + 6 = 0

Sekarang eliminasi nilai y dahulu, maka:
=> (2x – 3y + 17) + (3x + 2y + 6) = 0
=> 2(2x – 3y + 17) + 3(3x + 2y + 6) = 0
=> (4x – 6y + 34) + (9x + 6y + 18) = 0
=> 13x + 52 = 0, 13x = -52, maka x = -4.
Substitusi nilai x = -4 kedalam persamaan (2), maka:
=> 3(-4) + 2y + 6 = 0
=> -12 + 6 + 2y = 0
=> -6 + 2y = 0, maka y = 3.
Sekarang substitusi x dan y ke 4x – 5y, maka:
=> 4(-4) – 5(3) = -16 – 15 = -31