x^2-15x-7,75=0

Solution for x^2-15x-7,75=0 equation:

x^2-15x-7.75=0

a = 1; b = -15; c = -7.75;
Δ = b2-4ac
Δ = -152-4·1·(-7.75)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-16}{2*1}=\frac{-1}{2}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+16}{2*1}=\frac{31}{2}
=15+1/2
$