Răspuns:
[tex] 9{x}^{2} + 6x + 1 = 6x + 18 \sqrt{2} + 28[/tex]
[tex]9x^{2} + 6x - 6x = 18 \sqrt{2} + 28 - 1[/tex]
[tex]9x {}^{2} = 18 \sqrt{2} + 27[/tex]
[tex]x {}^{2} = \frac{18 \sqrt{2} }{9} + 27 \div 9[/tex]
[tex]x {}^{2} = 2 \sqrt{2} + 3[/tex]
[tex]x = + - \sqrt{2 \sqrt{2} + 3} [/tex]
