x^2+78x-216=0

Solution for x^2+78x-216=0 equation:

x^2+78x-216=0

a = 1; b = 78; c = -216;
Δ = b2-4ac
Δ = 782-4·1·(-216)
Δ = 6948
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:

$\sqrt{\Delta}=\sqrt{6948}=\sqrt{36*193}=\sqrt{36}*\sqrt{193}=6\sqrt{193}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(78)-6\sqrt{193}}{2*1}=\frac{-78-6\sqrt{193}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(78)+6\sqrt{193}}{2*1}=\frac{-78+6\sqrt{193}}{2}
$