Question 347195
Let {{{u=x^2}}}. then {{{u^2=x^4}}}
{{{3u^2+13u^2-10=0}}}
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{{{u = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{u = (-13 +- sqrt( 13^2-4*3*(-10) ))/(2*3) }}} 
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Once you solve for {{{u}}}, substitute back and find {{{x}}}.