SOLUTION: Find all real solutions of the equation. {{{ x^4-8x^2-9=0 }}}

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Question 784576: Find all real solutions of the equation.
+x%5E4-8x%5E2-9=0+
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Factoring,
+x%5E4-8x%5E2-9=0+ --> %28x%5E2-9%29%28x%5E2%2B1%29=0+ --> %28x%2B3%29%28x-3%29%28x%5E2%2B1%29=0+
x%5E2%2B1=0 has no real solutions, so we work from the other two factors
x%2B3=0 --> highlight%28x=-3%29
x-3=0 --> highlight%28x=3%29