x^2-9x-15x=-5

Solution for x^2-9x-15x=-5 equation:

x^2-9x-15x=-5

We move all terms to the left:

x^2-9x-15x-(-5)=0

We add all the numbers together, and all the variables

x^2-24x+5=0

a = 1; b = -24; c = +5;
Δ = b2-4ac
Δ = -242-4·1·5
Δ = 556
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:

$\sqrt{\Delta}=\sqrt{556}=\sqrt{4*139}=\sqrt{4}*\sqrt{139}=2\sqrt{139}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-24)-2\sqrt{139}}{2*1}=\frac{24-2\sqrt{139}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-24)+2\sqrt{139}}{2*1}=\frac{24+2\sqrt{139}}{2}
$