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