Bonsoir
développer et réduire
a) (-x+6)(2x-7)
= -x * 2x - x * (-7) + 6 * 2x - 6 * 7
= -2x^2 + 7x + 12x - 42
= -2x^3 + 19x - 42
b) (2x-1)(-x+3)-(x-5)(4x-7)
= -2x^2 + 6x + x - 3 - (4x^2 - 7x - 20x + 35)
= -2x^2 + 7x - 3 - 4x^2 + 27x - 35
= -6x^2 + 34x - 38
