(2x+1)(3x²-4x+5)-(3x-1)(3x²+x-2)+(x-3)(3x²+14x+1)=
6x³-8x²+10x+3x²-4x+5-(3x-1)(3x²+x-2)+(x-3)(3x²+14x+1)=
6x³-8x²+10x+3x²-4x+5-(9x³+3x²-6x-3x²-x+2)+(x-3)(3x²+14x+1)=
6x³-8x²+10x+3x²-4x+5-(9x³+3x²-6x-3x²-x+2)+3x³+14x²+x-9x²-42x-3=
6x³-8x²+10x+3x²-4x+5-(9x³-7x+2)+3x³+14x²+x-9x²-42x-3=
6x³-8x²+10x+3x²-4x+5-9x³+7x-2+3x³+14x²+x-9x²-42x-3=
-8x²+10x+3x²-4x+5+7x-2+14x²+x-9x²-42x-3=
10x-4x+5+7x-2+x-42x-3=
10x-4x+7x+x-42x+5-2-3=
6x+8x-42x+0=
14x-42x= -28x
