a) 5x^2-x=0
x(5x-1)=0
5x-1=0
5x=1
x=1/5
donc x=0 ou x=1/5
b) 2x(x+1)-(x+1)=0
2x^2+2x-x-1=0
2x^2+x-1=0
(2x-1)(x+1)=0
2x-1=0
x=1/2
2x+1=0
x=-1/2
donc x=1/2 ou x=-1/2
c) (2x-3)(x-4)+(2x-3)=0
2x^2-11x+12+2x-3=0
2x^2-9x+9=0
(2x-3)(x-3)=0
2x-3=0
x-3=0
donc x=3/2 ou x=3
d) (x-2)(4x+5)-(x-2)(3x-2)=0
4x^2-3x-10-3x^2+8x-4=0
x^2+5x-14=0
(x-2)(x+7)=0
x-2=0
x+7=0
donc x=/2 ou x=-7