a)
w(x)=(x+3)^2-(2x+1)^2=x^2+6x+9-(4x^2+4x+1)=
=x^2+6x+9-4x^2-4x-1=-3x^2+2x+8=-(3x^2-2x-8)=
=-(3x^2-6x+4x-8)=-[3x(x-2)+4(x-2)]=-(x-2)(3x+4)
b)
w(x)=(2x-4)^2-(2-x)^2=4x^2-16x+16-(4-4x+x^2)=
4x^2-16x+16-4+4x-x^2=3x^2-12x+12=3(x^2-4x+4)=3(x-2)^2
c)
w(x)=5(x-1)^5-20(x-1)^4=5(x-1)^4[(x-1)-4]=5(x-1)^4(x-5)
d)
w(x)=4(x+1)^5-8(x+1)^3=4(x+1)^3[(x+1)^2-2]=4(x+1)^3(x^2+2x+1-2)=4(x+1)^3(x^2+2x-1)