x2+15x-1125=0

Solution for x2+15x-1125=0 equation:

x2+15x-1125=0

We add all the numbers together, and all the variables

x^2+15x-1125=0

a = 1; b = 15; c = -1125;
Δ = b2-4ac
Δ = 152-4·1·(-1125)
Δ = 4725
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:

$\sqrt{\Delta}=\sqrt{4725}=\sqrt{225*21}=\sqrt{225}*\sqrt{21}=15\sqrt{21}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15\sqrt{21}}{2*1}=\frac{-15-15\sqrt{21}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15\sqrt{21}}{2*1}=\frac{-15+15\sqrt{21}}{2}
$