[tex]x= \frac{5 \pm 2 \sqrt{7} }{3} \\ x= \frac{5 + 2 \sqrt{7} }{3} \ or \ x= \frac{5 - 2 \sqrt{7} }{3} \\ (x-\frac{5 + 2 \sqrt{7} }{3})=0 \ or \ (x- \frac{5 - 2 \sqrt{7} }{3})=0 \\ (x-\frac{5 + 2 \sqrt{7} }{3})(x- \frac{5 - 2 \sqrt{7} }{3})=0 \\ (3x-(5 + 2 \sqrt{7}))(3x-(5 - 2 \sqrt{7}))=0 \\ 9x^2-3x(5-2 \sqrt{7} )-3x(5+2 \sqrt{7} )+(5+2 \sqrt{7} )(5-2 \sqrt{7} )=0 \\ 9x^2-15x+6 \sqrt{7} x-15x-6 \sqrt{7} x+25-28=0 \\ 9x^2-30x-3=0 \\ 3(3x^2-10x-1)=0 \\ 3x^2-10x-1=0[/tex]
