factoriser les calculs

a = (x-2)(x+8) +(x-2)(x+2)
a =(x-2)(x+8+x+2)
a =(x-2)(2x+10)
a = 2(x-2)(x+5)

b =(2x-5)(2x+5) -(2x-5)(x+8)
b = (2x-5)(2x+5-x-8)
b =(2x-5)(x-3)

c = (x-V3)(x+V3) +(x-V3)(2x+3V2)
c = (x-V3)(x+V3+2x+3V2)
c = (x-V3)(3x+3V2+V3)

les autres je ne sais pas