6x2-26x+9=0.

Solution for 6x2-26x+9=0. equation:

6x^2-26x+9=0.

a = 6; b = -26; c = +9;
Δ = b2-4ac
Δ = -262-4·6·9
Δ = 460
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{460}=\sqrt{4*115}=\sqrt{4}*\sqrt{115}=2\sqrt{115}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-2\sqrt{115}}{2*6}=\frac{26-2\sqrt{115}}{12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+2\sqrt{115}}{2*6}=\frac{26+2\sqrt{115}}{12}
$