solve

k (power 4) - k (power 2) - 12 = 0

sorry if this sounds stupid, im not good at maths :(

x = 2, or x = -2

thanks :)

would you mind telling me how you did that?

Welcome to the forums.

One way is to make the following substitution: k² = x. The equation then becomes x² - x - 12 = 0, which is a quadratic equation in x. The solutions of the quadratic equation are x = 4, -3, resulting in 4 solutions for k:

k = ± √x

k = ± √4 = ± 2

k = ± √-3 = ± i√3

thankyou very much for your help