[tex]\displaystyle\\
3x^2+2,01 = 2,1\\\\
3x^2 = 2,1 -2,01 \\\\
3x^2= 0,09\\\\
x^2 = \frac{0,09}{3}\\\\
x^2 = 0,03\\\\
x^2 = \frac{3}{100}\\\\
x = \pm \sqrt{\frac{3}{100}}= \pm \frac{ \sqrt{3} }{10}\\\\
x_1 = \boxed{\frac{ \sqrt{3} }{10}} \\\\
x_2 = \boxed{-\frac{ \sqrt{3} }{10}} \\\\ [/tex]
