vous pouvez m'aider svp ? developper et reduire: A= (3x-1)(x+1)(-2x+1) merci :)

a=(3x-1)(x+1)(-2x+1)
=3x[(x+1)(-2x+1)]-1[(x+1)(-2x+1)]
=[(3x²+3x)(-6x+3x)]-[(x+1)(-2x+1)]
=[3x²(-6x+3x)+3x(-6x+3x)]-[x(-2x+1)+1(-2x+1)]
=[3x²(-6x+3x)+(18x²+9x²)]-[(-2x²+x)+(-2x+1)]
=["....pareil... "+(37x²)]-[(-2x²+x)+(-2x+1)]
=3x²(-3x)+(37x²)-[-2x²+x+(-2x)+1]
=3x²*3x+37x²+2x²-3x+1
=3x²*3x+39x²-3x+1
=3x²+39x²+1
=42x²+1