Verified answer

If the equation is X^4 - 12x^2 -64 =0, there is.

Use u = x^2, now your equation will look like this:

u^2 - 12u - 64 =0

Find u1 and u2 using the quadratic formula.

The solutions are u1 = 16, u2 = -4

Now you go back to x, first deal with u1, then u2. Because u = x^2 each u solution will give you two x solutions.

u = x^2 = 16

x = +/- SQRT(16)

x1 = 4

x2 = -4

x2 = -4. This is not possible with real numbers. so it will give you two imaginary numbers. Do the same as before

x = +/- SQRT(-4) = +/- 2*SQRT(-1) = +/- 2i

x3 = i

x4 = -i

See my answer to your previous question.