What are the real or imaginary solutions of the polynomial equation x^4-52x^2+576?

the roots of the polynomial for this case will be x1 = 6, x2 = -6, x3 = 4, x4 = -4.You can solve the polynomial using the resolver after making the variable change u = x ^ 2 so that you have a second degree polynomial. Then return the change to find the missing roots. Attached solution.