Odpowiedź:
a) (3x - 2)(x + 1) = 3x² - 5
3x² + 3x - 2x - 2 = 3x² - 5
3x² + 3x - 2x - 3x² = - 5 + 2
x = - 3
b) (4 - 5x)(2 + x) = -(4 + 5x²)
8 + 4x - 10x - 5x² = - 4 - 5x²
4x - 10x - 5x² + 5x² = - 4 - 8
- 6x = - 12 | : (- 6)
x = 2
c) 4x² - 2x = (2x + 1)(2x - 3)
4x² - 2x = 4x² - 6x + 2x - 3
4x² - 2x - 4x² + 6x - 2x = - 3
2x = - 3 | : 2
x = - 3/2
d) 3x(2x + 5) = (x + 3)(6x + 1)
6x² + 15x = 6x² + x + 18x + 3
6x² + 15x - 6x² - x - 18x = 3
- 4x = 3 | : ( - 4)
x = - ¾
