(4x-3)²-(x+2)²
= 16x²-24x+9-(x²+4x+4)
=16x²-24x+9-x²-4x-4
=15x²-28x+5
x(x+1)(x-2)
=(x²+x) (x-2)
=x³-2x²+x²-2x
=x³-x²-2x
(2x-1)(x+3)(x+1)
=(2x²+6x-x-3)(x+1)
= 2x³+2x²+6x²+6x-x²-x-3x-3
=2x³+7x²+2x-3
(2y-1)²(y+2)
=(4y²-4y+1)(y+2)
=4y³+8y²-4y²-8y+y+2
=4y³+4y²-7y+2
(x+y)²-(x-y)²
=x²+2xy+y²-(x²-2xy+y²)
=x²+2xy+y²-x²+2xy-y²
=4xy
il restera 200²=40000
