1) (14y+21) (1.8-0.3y) = 0

2) 2 (4x+1) - x=7x+3

1.

(14y + 21) = 0, или (1.8 - 0.3y) = 0

1) 14y + 21 = 0

14y = - 21

y = - 1.5

2) 1.8 - 0.3y = 0

18 - 3y = 0

-3y = - 18

y = 6

Ответ: y1 = - 1.5;

y2 = 6.

2.

2 (4x - 1) - x = 7x + 3;

8x + 2 - x = 7x + 3;

8x - x - 7x = 3 - 2;

0 ≠ 1 = > (корней нет).