Solve.
-$x ^ { 4 } - 23 x ^ { 2 } = 50$
A) $\{ 5 , \mathrm { i } \sqrt { 2 } \}$
B) $\{ - 25,2 \}$
C) $[ - 5,5 , - \mathrm { i } \sqrt { 2 } , \mathrm { i } \sqrt { 2 } \}$
D) $\{ - \sqrt { 2 } , \sqrt { 2 } , - 5 i , 5 i \}$

Question

Quizplus · Accepted Answer

This equation can be solved by substituting $y = x^2$, turning it into a quadratic equation $y^2 - 23y - 50 = 0$. Solving this gives $y = 25$ or $y = -2$. Substituting back $x^2 = 25$ gives $x = 5$ or $x = -5$, and $x^2 = -2$ gives $x = i\sqrt{2}$ or $x = -i\sqrt{2}$.

Solve - x4−23x2=50x ^ { 4 } - 23 x ^ { 2 } = 50x4−23x2=50

Solve
- $x ^ { 4 } - 23 x ^ { 2 } = 50$