-x^2+12x+36=0

Solution for -x^2+12x+36=0 equation:

-x^2+12x+36=0

We add all the numbers together, and all the variables

-1x^2+12x+36=0

a = -1; b = 12; c = +36;
Δ = b2-4ac
Δ = 122-4·(-1)·36
Δ = 288
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:

$\sqrt{\Delta}=\sqrt{288}=\sqrt{144*2}=\sqrt{144}*\sqrt{2}=12\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-12\sqrt{2}}{2*-1}=\frac{-12-12\sqrt{2}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+12\sqrt{2}}{2*-1}=\frac{-12+12\sqrt{2}}{-2}
$