Bsr
J'y ai déjà répondu mais je le refait.
1) (2x-3)² = 81
1) 2x-3 = ±9
1) 2x-3 = -9 ; 2x-3 = 9
1) x = -3 ; 2x-3 = 9
1) x = -3 ; x = 6
Équation à 2 solutions → x1 = 6 ; x2 = -3
2)(2x-4)(x-1)-(x-1)(-x-5) = 0
2) (x-1)(2x-4-(-x-5)) = 0
2) (x-1)(2x-4+x+5) = 0
2) (x-1)(3x-4+5) = 0
2) (x-1)(3x+1) = 0
2) x-1 = 0 ; 3x+1 = 0
2) x = 1 ; 3x+1 = 0
2) x = 1 ; x = -1/3
Équation à 2 solutions → x1 = -1/3 ; x2 = 1
3) (7x-8)²-(5x-9)² = 0
3) (7x-8-(5x-9))(7x-8+(5x-9)) = 0
3) (7x-8-5x+9)(7x-8+(5x-9)) = 0
3) (7x-8-5x+9)(7x-8+5x-9) = 0
3) (2x-8+9)(7x-8+5x-9) = 0
3) (2x+1)(7x-8+5x-9) = 0
3) (2x+1)(12x-8-9) = 0
3) (2x+1)(12x-17) = 0
3) 2x+1 = 0 ; 12x-17 = 0
3) x = -1/2 ; 12x-17 = 0
3) x = -1/2 ; x = 17/12
Équation a 2 solutions → x1 = 17/12 ; x2 = -1/2
Voilà !
