You can put this solution on YOUR website! Try this, 1st factor out one 'x' and get:
x(x^4-5x^2+4)
now factor what remains in the parenthesis and get:
(x^4-5x^2+4)
factor by grouping:
(x^4-4x^2)(-x^2+4)
x^2(x^2-4)-(x^2-4)
(x^2-4)(x^2-1)
bring down the intial x factored out:
ans= x(x^2-4)(x^2-1)
