Завдання:
Розкрий дужки:
1) 2(m + 1);
2) 3(x – 4);
3) –5(2x + 1);
4) (–1,6x + 2) ⋅ (–5);
5) (–2x – y) ⋅ 3;
6) –7(x – 2);
7) (a – b) ⋅ (–3);
8) (–4a + 5b) ⋅ 2.
Розв'язок:
1) 2(а + 1) = 2 ⋅ а + 2 ⋅ 1 = 2а + 2
2) 3(х – 4) = 3 ⋅ х – 3 ⋅ 4 = 3х – 12
3) -5(2х + 1) = -5 ⋅ 2х + (-5) ⋅ 1 = -10х – 5
4) (-1,6х + 2) ⋅ (-5) = -1,6 ⋅ (-5) + 2 ⋅ (-5) = 8х – 10
5) (-2х – у) ⋅ 3 = -2х ⋅ 3 – у ⋅ 3 = -6х – 3у
6) -7 ⋅ (х – 2) = -7 ⋅ х – 7 ⋅ (-2) = -7х + 14
7) (a – b) ⋅ (-3) = -3a – b ⋅ (-3) = -3a + 3b
8) (-4a + 5b) ⋅ 2 = -4a ⋅ 2 + 5b ⋅ 2 = -8a + 10b