10x^2+12x-81=0

Solution for 10x^2+12x-81=0 equation:

10x^2+12x-81=0

a = 10; b = 12; c = -81;
Δ = b2-4ac
Δ = 122-4·10·(-81)
Δ = 3384
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:

$\sqrt{\Delta}=\sqrt{3384}=\sqrt{36*94}=\sqrt{36}*\sqrt{94}=6\sqrt{94}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-6\sqrt{94}}{2*10}=\frac{-12-6\sqrt{94}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+6\sqrt{94}}{2*10}=\frac{-12+6\sqrt{94}}{20}
$