équations : a) 3 - (5x + 1) = 8x + (4 - 2x) b) 8 - 3 (2x - 4) = 5x - (x + 1)

Je te propose cette solution, attention aux changements de signes (j'espère ne pas m'être trompé !)

[tex]3 - (5x + 1) = 8x + (4 - 2x) \\ 3 - 5x - 1 = 8x + 4 - 2x \\ 3-1-5x = 8x-2x +4 \\ 2 - 5x = 6x + 4 \\ 2 - 4 = +5x + 6x \\ - 2 = 11x \\ - \frac{2}{11} = x \\ \\ \\ 8 - 3 (2x - 4) = 5x - (x + 1) \\ 8 - 6x + 12 = 5x - x - 1 \\ 20 - 6x = 4x - 1 \\ 20 + 1 = 6x + 4x \\ 21 = 10x \\ \frac{21}{10} = x \\ [/tex]