Вправи: 280

280. Виконайте множення:

1) 17a²b (1,4a² – 2,1b³) = 17a²b ∙ 1410a² – 17a²b ∙ 2110b³ = 15a⁴b – 310a²b⁴;

2) –23x²y³ ∙ (1,2y⁵ – 910xy) = –23x²y³ ∙ 1210y⁵ + (–23x²y³) ∙ (–910xy) =

= –0,8x²y⁸ + 0,6x³y⁴;

3) (115mn² – 1115m²) ∙ (–56m²n) = 65mn² ∙ (–56m²n) + 1615m² ∙ 56m²n =

= –m³n³ – 89m⁴n;

4) (114m – 56n) ∙ 225m²n⁷ = 54m ∙ 125m²n⁷ – 56n ∙ 125m²n⁷ = 3m³n⁷ – 2m²n⁸.