Вправи: 368

368. Розв’яжи рівняння.

a) (x – 2)(x + 5) = x² + 2;

x² + 5x – 2x – 10 = x² + 2;

3x = 10 + 2;

3x = 12|: 3;

x = 4.

б) (x – 6)(x – 2) – x(x + 2) = 2;

x2 – 2x – 6x + 12 – x2 – 2x = 2;

–10x = –12 + 2;

–10x = x10|: (–10);

x = 1.

в) (x – 1)(x + 5) = (x + 2)(x + 3);

x² + 5x – x – 5 = x² + 3x + 2x + b;

4x – 5x = 5 + 6;

–x = 11;

x = –11.

г) (2x + 3)(x – 7) + 6 = (x + 3)(2x + 1);

2x² – 14x + 3x – 21 + 6 = 2x² + x + 6x + 3;

–11x – 7x = 21x – 6 + 3;

–18x = 18|: (–18);

x = –1.