SOLUTION: x^6-3x^3-18=0

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Question 180459: x^6-3x^3-18=0
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Use a subsitution to transform this equation to a quadratic equation.
Let z=x%5E3, then
x%5E6-3x%5E3-18=z%5E2-3z-18=0
%28z-6%29%28z%2B3%29=0
First solution:
z-6=0
z=6
x%5E3=6
x=6%5E%281%2F3%29
Second solution:
z%2B3=0
z=-3
x%5E3=-3
x=-3%5E%281%2F3%29