Let u = x^2
Then you get 4u^2 -13u +9
You can factorise this using the quadratic formula:
u=9/4 and 1
:. (4u-9)(u-1)
now sub back in the u = x^2
and you get (4x^2 -9)(x^2 -1)
you can factorise this further using the difference of 2 squares for both of the above brackets
=(2x - 3)(2x+3)(x-1)(x+1)