Question

how to solve x^4-33x^2+200=0

Answer 1

x^4-33x^2+200=0        (factor that out)
x^4-33x^2+200 -----> (x^2-8)(x^2-25)

new equation:
x^2-8=0     x^2-25=0            (solve for x for both equations)
   x^2=8         x^2 =25      

the x's are still squared so you have the square root both sides of the equations to get rid of the ^2:

x^2=8        x^2=25
$\sqrt{ x^{2} } = \sqrt{8}$    $\sqrt{x ^{2} } = \sqrt{25}$

x=$2 \sqrt{2}$   x=5