Завдання 1402 - 1500 » 1440

Розв’яжіть рівняння: 1) 7(х + 2) = –14; 7х + 14 = –14; 7х = —14 – 14; 7х = –28; х = –4. 2) 8y = 2(5 – y); 8y = 10 – 2y; 8y + 2y = 10; 10y = 10; y = 1. 3) 2(3х – 4) = 4(х – 3); 6х – 8 = 4х – 12; 6х – 4х = –12 + 8; 2х = –4; х = –2. 4) 7(х + 3) – 2(х – 5) = 8; 7х + 21 – 2х + 10 = 8; 5х = 8 – 31; 5х = –23; х = –4,6. 5) 5 + 3(2y – 1) = 2(у – 3); 5 + 6y – 3 = 2y – 6; 6y – 2y = –6 – 2; 4y = –8; y = –2. 6) –х – 5,2 = 12 – 2(х + 0,6) – 10; –х – 5,2 = 12 – 2 х –1,2 – 10; –х + 2х = 0,8 + 5,2; х = 6.