Завдання:
Розкрий дужки:
1) 3(a + 1);
2) 2(b – 3);
3) –6(2a + 1);
4) 5(–1,4x + 2);
5) (–2,5x + 3) ⋅ 4;
6) (a – 1) ⋅ (–1,5);
7) (–x + y) ⋅ (–1,3);
8) (2a – 10b) ⋅ 7.
Розв'язок:
1) 3(а + 1) = 3 ⋅ а + 3 ⋅ 1 = 3а + 3
2) 2(b – 3) = 2 ⋅ b – 2 ⋅ 3 = 2b – 6
3) -6(2a + 1) = -6 ⋅ 2a – 6 ⋅ 1 = -12a – 6
4) 5(-1,4х + 2) = 5 ⋅ (-1,4х) + 5 ⋅ 2 = -7х + 10
5) (-2,5х + 3) ⋅ 4 = -2,5 ⋅ 4 + 3 ⋅ 4 = -10х + 12
6) (а – 1) ⋅ (-1,5) = -1,5а – 1 ⋅ (-1,5) = -1,5а + 1,5
7) (-х + у) ⋅ (-1,3) = -х ⋅ (-1,3) + у ⋅ (-1,3) = 1,3х – 1,3у
8) (2a – 10b) ⋅ 7 = 2a ⋅ 7 – 10b ⋅ 7 = 14a – 70b