Question

на фото только бистрей

Answer 1

$0.5(1.6x - 6.4y) - 2.4(1.5x + y) = \\ 0.8x - 3.2y - 3.6x - 2.4y = \\ - 2.8x - 5.6y = - 2.8 \times 3 - 5.6 \times ( - 4.5) = \\ - 8.4 + 25.2 = 16.8$