Solve. Express any nonreal complex numbers with i notation.
-$$x ^ { 4 } - 40 x ^ { 2 } + 144 = 0$$
A) $x = 2,6$
B) $x = \pm 2 i , \pm 6 \mathrm { i }$
C) $x = \pm 2 , \pm 6$
D) $x = 4,36$

Question

Quizplus · Accepted Answer

This equation can be solved by substituting $y = x^2$, turning it into a quadratic equation $y^2 - 40y + 144 = 0$. Solving this gives $y = 36$ and $y = 4$, which means $x^2 = 36$ and $x^2 = 4$. Thus, $x = \pm 6$ and $x = \pm 2$, respectively.

Solve Express Any Nonreal Complex Numbers with I Notation x4−40x2+144=0x ^ { 4 } - 40 x ^ { 2 } + 144 = 0x4−40x2+144=0

Solve Express Any Nonreal Complex Numbers with I Notation $x ^ { 4 } - 40 x ^ { 2 } + 144 = 0$