u^2-26u+10=0

Solution for u^2-26u+10=0 equation:

u^2-26u+10=0

a = 1; b = -26; c = +10;
Δ = b2-4ac
Δ = -262-4·1·10
Δ = 636
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{636}=\sqrt{4*159}=\sqrt{4}*\sqrt{159}=2\sqrt{159}$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-2\sqrt{159}}{2*1}=\frac{26-2\sqrt{159}}{2}
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+2\sqrt{159}}{2*1}=\frac{26+2\sqrt{159}}{2}
$