Решите ривнення: 1) (5х + 1) (2х - 3) - (10х - 9) (х + 2) 2) (7х - 1) (х + 5) = (3 + 7х) (х + 3).

ответ:

1) (5x + 1)(2х - 3) = (10x - 9)(x + 2);
10x2 - 15х + 2х - 3 = 10x2 + 20х - 9х - 18;
-24х = -15;
x = 5/8;

2) (7x - 1)(х + 5) = (3 + 7x)(x + 3);
7х2 + 35х - x - 5 = 3x + 9 + 7х2 + 21x;
10x = 14;
x = 1,4.