16=x^2+6x-16

Solution for 16=x^2+6x-16 equation:

16=x^2+6x-16

We move all terms to the left:

16-(x^2+6x-16)=0

We get rid of parentheses

-x^2-6x+16+16=0

We add all the numbers together, and all the variables

-1x^2-6x+32=0

a = -1; b = -6; c = +32;
Δ = b2-4ac
Δ = -62-4·(-1)·32
Δ = 164
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:

$\sqrt{\Delta}=\sqrt{164}=\sqrt{4*41}=\sqrt{4}*\sqrt{41}=2\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{41}}{2*-1}=\frac{6-2\sqrt{41}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{41}}{2*-1}=\frac{6+2\sqrt{41}}{-2}
$