zad. 14
a) (3x - 2)(x + 1) = 3x² - 5
3x² + 3x - 2x - 2 = 3x² - 5
3x² + x - 2 = 3x² - 5 / -3x² / +2
x = -3
b) (4 - 5x)(2 + x) = -(4 + 5x²)
8 + 4x - 10x - 5x² = -4 - 5x²
-5x² - 6x + 8 = -5x² - 4 / + 5x² / -8
-6x = -12 /: (-6)
x = 2
c) 4x² - 2x = (2x + 1)(2x - 3)
4x² - 2x = 4x² - 6x + 2x - 3
4x² - 2x = 4x² - 4x - 3 / -4x² / +4x
2x = -3 /: 2
x = - ⅔
d) 3x(2x + 5) = (x + 3)(6x + 1)
6x² + 15x = 6x² + x + 18x + 3
6x² + 15x = 6x² + 19x + 3 / -6x² / -19x
-4x = 3 /: (-4)
x = - ¾
;)
