0 \\
x_{1} = \frac{6+ \sqrt{36-28} }{2} = \frac{6+ \sqrt{8} }{2} = \frac{2(3+ \sqrt{2} )}{2} =3+ \sqrt{2} \\
x_{2} = \frac{6- \sqrt{36-28} }{2} = \frac{6- \sqrt{2} }{2} = \frac{2(3- \sqrt{2}) }{2} =3- \sqrt{2} " alt=" x^{2} -6x+7=0 \\
D>0 \\
x_{1} = \frac{6+ \sqrt{36-28} }{2} = \frac{6+ \sqrt{8} }{2} = \frac{2(3+ \sqrt{2} )}{2} =3+ \sqrt{2} \\
x_{2} = \frac{6- \sqrt{36-28} }{2} = \frac{6- \sqrt{2} }{2} = \frac{2(3- \sqrt{2}) }{2} =3- \sqrt{2} " align="absmiddle" class="latex-formula">