-x^2+8x+47=0

Solution for -x^2+8x+47=0 equation:

-x^2+8x+47=0

We add all the numbers together, and all the variables

-1x^2+8x+47=0

a = -1; b = 8; c = +47;
Δ = b2-4ac
Δ = 82-4·(-1)·47
Δ = 252
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:

$\sqrt{\Delta}=\sqrt{252}=\sqrt{36*7}=\sqrt{36}*\sqrt{7}=6\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-6\sqrt{7}}{2*-1}=\frac{-8-6\sqrt{7}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+6\sqrt{7}}{2*-1}=\frac{-8+6\sqrt{7}}{-2}
$