Bonsoir,
(2x+5)(3x+7) = 6x²+14x+15x+35 = 6x²+29x+35
(5x+8)(2x-6) = 10x²-30x+16x-48 = 10x²-14x-48
(-1,5x-3)(4x-0,5) = -6x²+0,75x-12x+1,5 = -6x²-11,25x+1,5
(8x-7)(-7x+7) = -56x²+56x+49x-49 = -56x²+105x-49
6+(5y-2)(3-4y) = 6+(15y-20y²-6+8y) = -20y²+23y
5z-(4z+3)(-2z-5) = 5z-(-8z²-20z-6z-15) = 5z+8z²+20z+6z+15 = 8z²+31z+15
6(2x-1)(3-x) = 6(6x-2x²-3+x) = 6(-2x²+7x-3) = -12x²+42x-18
(x+7)(3-2x)+(5x-2)(4x+1) = (3x-2x²+21-14x)+(20x²+5x-8x-2)
= 18x²-14x+19
