Developper aidez moi svp

a = 3 (x+1)²  -(2x+2)²
 a= 3(x²+2x+1) - (4x²+8x+4)
a= 3x² +6x +3 -4x²-8x-4
a =  -x²-2x -1

b =3 (2x)(3x-4)
b = 3 (6x²-8x)
b = 18x² -24x

c = (1/2t+4)² -4(t+1/4)²
c= (1/4t² +4t +16) -4 (t² +1/2t +1/8)
c= 1/4t² +4t +16 -4t² -2t -1/4
c = 1/4t² -4t² +2t +16-1/4
c = 1/4t² -16/4t² +2t +64/4 -1/4
c =-15/4 t² +2t +63/4

d =(x+2)cube
d = (x+2)(x+2)²
d= (x+2) (x²+4x+4)
d= xau cube +4x²+4x+2x²+8x+8
d= x au cube +6x² +12x +8