Завдання 1402 - 1500 » 1435 (7-8)

7) –2x + 4 = –1/3x – 21; –2x + 1/3x = –21 – 4; –12/3x = –25; 5/3x = 25; x = 25 ∙ 3/5; x = 15. 8) 2/3y + 2 = 1/2y – 1/4y – 3; 2/3y – 1/2y + 1/4y = –2 –3; 8/12y – 6/12y + 3/12y = –5; 5/12y = –5; y = –5 : 5 ∙ 12; y = –12.