Question

What are the real and complex solutions of the polynomial equation x^4+3x^2-4

Answer 1

Answer: (D) -1,1,-2i,2i

Explanation:

$x^4+3x^2-4 = 0\\x^2 \rightarrow z\\z^2 + 3z -4 = 0 \\z_1 = -4\\z_2 = 1\\x_{1,2} = \pm\sqrt{-4}=\pm 2 i\\x_{3,4} = \pm 1$