Завдання 1301 - 1402 » 1357

Розв’яжи рівняння: 1) –23/7х + 35/6х – 18/21х = – 1/2; 1/42х = – 1/2; х = – 1/2 : 1/42; х = –21. 2) –4(2х – 5) + 3(5х – 7) = –15; –4 · 2х + 4 · 5 + 3 · 5х – 3 · 7 = –15; –8х + 20 + 15х – 21 = –15; 7х – 1 = – 15; 7х = –15 + 1; 7х = –14; х = –14 : 7; х = –2. 3) |4x| + 7 = 9; |4x| = 9 – 7; |4x| = 2; 4х = 2 або 4х = –2; х = 2 : 4; х = 0,5 х = –2 : 4; х = –0,5. 4) |2x – 3| = 5; 2х – 3 = 5 або 2х – 3 = – 5; 2х = 5 + 3 2х = 8 х = 8 : 2 х = 4 2х = –5 + 3; 2х = –2; х = –2 : 2; х = –1.