9x^2-18x-80=4

Solution for 9x^2-18x-80=4 equation:

9x^2-18x-80=4

We move all terms to the left:

9x^2-18x-80-(4)=0

We add all the numbers together, and all the variables

9x^2-18x-84=0

a = 9; b = -18; c = -84;
Δ = b2-4ac
Δ = -182-4·9·(-84)
Δ = 3348
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:

$\sqrt{\Delta}=\sqrt{3348}=\sqrt{36*93}=\sqrt{36}*\sqrt{93}=6\sqrt{93}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-6\sqrt{93}}{2*9}=\frac{18-6\sqrt{93}}{18}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+6\sqrt{93}}{2*9}=\frac{18+6\sqrt{93}}{18}
$