Question 872287
Try a substitution, like u=x^2, and then solve for u.  You next must solve for x from reversing the substitution.  You may find four different solutions.


{{{(u-4)(u-8)=0}}}
u=4 OR u=8.


{{{x^2=4}}}
x=-2 or x=2;


{{{x^2=8}}}
x=-sqrt(2*2*2)=-2*sqrt(2)
or 
x=2*sqrt(2)


SUMMARY OF SOLUTION
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{{{x=-2}}} OR {{{x=2}}} OR {{{x=-2sqrt(2)}}} OR {{{x=2sqrt(2)}}}
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