bsr
A - j'enlève les ( ) : on aura :
2x - 5 = x - 3x - 4
2x - 5 + 5 = -2x - 4 + 5
2x + 2x = -2x + 2x + 1
4x = 1
x = 1/4 = 0,25
et
(3*5) / (5x*5) + 1*5x/(5*5x) = (2*5)/(5x*5) - 1*5x/5*5x
15/25x² + 5x/25x² = 10/25x² - 5x/25x²
(15+5x) / 25x² = (10-5x) / 25x²
donc
15 + 5x = 10 - 5x
10x = -5
x = -1/2 = -0,5
