a)
(x+1)^2-(x-1)^2+(x+2)^2+(2-x)^2=
=x^2+2x+1-(x^2-2x+1)+x^2+4x+4+4-4x+x^2=
=x^2+2x+1-x^2+2x-1+2x^2+8=
=2x^2+4x+8=
=2(x^2+2x+4)
b)
2(3+x)^2-(2-x)^2-3(2-x)(2+x)=
=2(9+6x+x^2)-(4-4x+x^2)-3(4-x^2)=
=18+12x+2x^2-4+4x-x^2-12+3x^2=
=4x^2+16x+2=
=2(2x^2+8x+1)
c)
(4x-3y)(4x+3y)-2(4x+3y)^2+2(3x-4y)^2=
=(4x)^2-(3y)^2-2(16x^2+24xy+9y^2)+2(9x^2-24xy+16y^2)=
=16x^2-9y^2-32x^2-48xy-18y^2+18x^2-48xy+32y^2=
=2x^2-96xy+5y^2