Answer :
x^4 + (6x)^2 - 7
multiply 6x^2
6x * 6x = 36x^2
x^4 + 36 * x^2 - 7
cannot be factored more
multiply 6x^2
6x * 6x = 36x^2
x^4 + 36 * x^2 - 7
cannot be factored more