a^2-25a-108=0

Solution for a^2-25a-108=0 equation:

a^2-25a-108=0

a = 1; b = -25; c = -108;
Δ = b2-4ac
Δ = -252-4·1·(-108)
Δ = 1057
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-\sqrt{1057}}{2*1}=\frac{25-\sqrt{1057}}{2}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+\sqrt{1057}}{2*1}=\frac{25+\sqrt{1057}}{2}
$