4x^4 – 37х^² + 9 = 0
(x² + 2х)² - 2(x² +2х) = 3.
(x² + 9)/ x = 2x

$4 x^{4} -37 x^{2} +9=0$
пусть $x^{2}$ =y
$4 y^{2} -37y+9=0$
D= $b^{2}$ -4ac=1369-4*4*9=1225
$y_{1}$ = $frac{-b+ sqrt{D} }{2a}$ = $frac{37+35}{8}=9$
$y_{2}=[tex] frac{-b- sqrt{D} }{2a}= frac{37-35}{8}=0.25$
$x^{2} =9$ или $x^{2}$ =0,25
x=3 x=0.5
Ответ: 3; 0,5