Question

Rozwiąż równania :
a)
(2x -5)(x+1) - 2 = (1-x)(8-2x) +2x
b)
(x - 3)(5 - x) - 2 = (2 -x)(x-4) +3
c)
(x - 5)(x +2)-(3-x)(2-x)= x-12

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Answer 1

A )
(2x -5)(x+1) - 2 = (1-x)(8-2x) +2x
2x² + 2x - 5x - 5 - 2 = 8 - 2x - 8x + 2x² + 2x
2x² - 3x - 7 = 2x² - 8x + 8
2x² - 3x - 2x² - 8x = 8 + 7
- 11x = 15 / : (-11)
x = - 15/11

b)
(x - 3)(5 - x) - 2 = (2 -x)(x-4) +3
5x - x² - 15 + 3x - 2 = 2x - 8 - x² + 4x + 3
8x - x² - 17 = 6x - 5 - x²
8x - x² - 6x + x² = - 5 + 17
2x = 12 / : 2
x = 6

c)
(x - 5)(x +2)-(3-x)(2-x)= x-12
x² + 2x - 5x - 10 - (6 - 3x - 2x + x² ) = x -12
x² - 3x - 10 - 6 + 3 + 2x - x² = x - 12
- x - x = - 12 + 16
- 2x = 4 / : (-2)
x = -2