Question 353894
HI,
2x^4/3 + 5x^2/3 -13 =0 
.
2x^4 + 5x^2 -39 =0 

*Note: This is a bi-quadratic form of an equation. In General:
The bi-quadratic equation is ax4 + bx2 + c = 0 and as it can be writen as:.
.
{{{a(x2)^2+bx2+c=0}}} has the roots:
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{{{x^2 = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
.
{{{x^2 = (-5 +- sqrt( 5^2-4*2*(-39) ))/(2*2) }}}
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{{{x^2 = (-5 +- sqrt( 5^2-4*2*(-39) ))/(2*2) }}}
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{{{x^2 = (-5 +- sqrt( 337))/4 }}}
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{{{x = sqrt((-5 +- sqrt( 337))/4 )}}}
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{{{x = (-5 + sqrt( 337))/4 }}} or {{{x = (-5 - sqrt( 337))/4 )}}}
or

{{{x = -((-5  + sqrt( 337))/4) }}} or {{{x = -((-5  - sqrt( 337))/4) }}}