Question

What are the roots of the polynomial function x^4 +7x^2-144=0

Answer 1

Explanation:

`x^4+7x^2-144=0\\x^4+16x^(2) -9x^(2) -144=0\\x^(2) (x^(2) +16)-9(x^(2) +16)=0\\(x^(2) +16)(x^(2) -9)=0\\(x^(2) -(-16))(x^(2) -3^2)=0\\(x^(2) -16 \iota^2)(x+3)(x-3)=0\\(x^(2) -(4\iota)^2)(x+3)(x-3)=0\\(x+4\iota)(x-4\iota)(x+3)(x-3)=0\\x=\pm4 \iota,\pm3`