Question 440057
{{{4x^4 - 37x^2 + 9 = 0}}}

<==> {{{4(x^2)^2 - 37x^2 + 9 = 0}}}

If you let {{{w = x^2}}}, then the original equation becomes 

 {{{4w^2 - 37w + 9 = 0}}}