Solve Equations That Are Quadratic in Form
Solve the Equation $$x ^ { 4 } - 20 x ^ { 2 } + 64 = 0$$

Multiple Choice

Solve Equations That Are Quadratic in Form
Solve the equation by making an appropriate substitution.
- $$x ^ { 4 } - 20 x ^ { 2 } + 64 = 0$$

A) $\{ - 2,2 , - 4,4 \}$
B) $\{ 4,16 \}$
C) $\{ 2,4 \}$
D) $\{ - 2 \mathrm { i } , 2 \mathrm { i } , - 4 \mathrm { i } , 4 \mathrm { i } \}$