Bonjour,
Développer:
(2x-3)(-5x+4)-(2x-3)²4/7(2x-3)= -10x²+15x+8x-12-4/7(2x-3)(2x-3)(2x-3)
= -10x²+23x-12-4/7(2x-3)(4x²-6x-6x+9)
= -10x²+23x-12-4/7(2x-3)(4x²-12x+9)
= -10x²+23x-12-4/7(8x³-24x²+18x-12x²+36x+27)
= -10x²+23x-12-4/7(8x³-36x²+54x-27)
= -10x²+23x-12-32x³/7+144x²/7-216x/7+ 108/7
= (-10x²*7+23x*7-12*7-32x³+144x²-216x+ 108)/7
= (-70x²+161x-84-32x³-144x²+216x- 108)/7
= (-32x²+74x²-55x+24)/7
