Bonsoir,
2x - 4 = 7
2x = 7 + 4
2x = 11
x = 11/2
(3x + 6)(x - 7) = 0
3x + 6 = 0 ou x - 7 = 0
3x = -6 ou x = 7
x = -6/3 = -2 ou x = 7
(2x+1)/(x+10) = 0
Df = R\{-10)
2x + 1 = 0 → 2x = -1 → x = -1/2
√x = 15
(√x)² = 15²
x = 225
1/x = 8
1/x × (x) = 8x
8x = 1
x = 1/8
x² = 10 → x = ± √10