Question

elect all solutions of 𝑥^4 −3⁢𝑥^2 −10 =0.

Answer 1

Let y = x^2. Then y^2 − 3y − 10 = 0 → (y − 5)(y + 2) = 0, so y = 5 or y = −2.

Thus x^2 = 5 → x = ±√5, and x^2 = −2 → x = ± i√2.

All solutions: x = ±√5, ± i√2.