Question 334892
{{{x^4+2x^2<=0}}}
{{{x^2(x^2+2)<=0}}}
Neither quantity is ever less than zero. 
Use the zero product property to find when it equals zero.
{{{x^2=0}}}
{{{x=0}}}
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{{{x^2+2=0}}}
{{{x^2=-2}}}
No solution.
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{{{x=0}}} is the only solution.
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{{{graph(300,300,-10,10,-10,10,x^4+2x^2)}}}