x2-0.15x-10000=0

Solution for x2-0.15x-10000=0 equation:

x2-0.15x-10000=0

We add all the numbers together, and all the variables

x^2-0.15x-10000=0

a = 1; b = -0.15; c = -10000;
Δ = b2-4ac
Δ = -0.152-4·1·(-10000)
Δ = 40000.0225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.15)-\sqrt{40000.0225}}{2*1}=\frac{0.15-\sqrt{40000.0225}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.15)+\sqrt{40000.0225}}{2*1}=\frac{0.15+\sqrt{40000.0225}}{2}
$