X2-12x-85=0

Solution for X2-12x-85=0 equation:

X2-12X-85=0

We add all the numbers together, and all the variables

X^2-12X-85=0

a = 1; b = -12; c = -85;
Δ = b2-4ac
Δ = -122-4·1·(-85)
Δ = 484
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{484}=22$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-22}{2*1}=\frac{-10}{2}
=-5
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+22}{2*1}=\frac{34}{2}
=17
$