a: =(x^2-1)^2
=(x-1)^2*(x+1)^2
b: =(x-y)*(x+y)+5(x-y)
=(x-y)(x+y+5)
c: =y^2-(2x-1)^2
=(y-2x+1)(y+2x-1)
d: =(x+2)^2(x^3-1)-(x^3-1)
=(x^3-1)(x+1)(x+3)
=(x-1)(x^2+x+1)(x+1)(x+3)
a)
\(=x^4-2x^2+1=\left(x^2-1\right)^2=\left(x^2-1\right)\left(x^2-1\right)=\left(x-1\right)\left(x+1\right)\left(x-1\right)\left(x+1\right)=\left(x-1\right)^2\left(x+1\right)^2\)
b)
\(=\left(x^2-y^2\right)-\left(5x-5y\right)\)
\(=\left(x-y\right)\left(x+y\right)-5\left(x-y\right)=\left(x-y\right)\left(x+y-5\right)\)
c)
\(=y^2-\left(4x^2-4x+1\right)\)
\(=y^2-\left(2x-1\right)^2=\left(y-2x+1\right)\left(y+2x-1\right)\)
d)
\(=\left(x+2\right)^2\left(x^3-1\right)+\left(1-x^3\right)\)
\(=\left(x^3-1\right)\left[\left(x+2\right)^2+1\right]\)
\(=\left(x-1\right)\left(x^2+x+1\right)\left(x^2+2x+4+1\right)\)
\(=\left(x-1\right)\left(x^2+x+1\right)\left(x^2+2x+5\right)\)


