x^2-30x+166=0

Solution for x^2-30x+166=0 equation:

x^2-30x+166=0

a = 1; b = -30; c = +166;
Δ = b2-4ac
Δ = -302-4·1·166
Δ = 236
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:

$\sqrt{\Delta}=\sqrt{236}=\sqrt{4*59}=\sqrt{4}*\sqrt{59}=2\sqrt{59}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{59}}{2*1}=\frac{30-2\sqrt{59}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{59}}{2*1}=\frac{30+2\sqrt{59}}{2}
$