16=x^2-10x-25

Solution for 16=x^2-10x-25 equation:

16=x^2-10x-25

We move all terms to the left:

16-(x^2-10x-25)=0

We get rid of parentheses

-x^2+10x+25+16=0

We add all the numbers together, and all the variables

-1x^2+10x+41=0

a = -1; b = 10; c = +41;
Δ = b2-4ac
Δ = 102-4·(-1)·41
Δ = 264
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:

$\sqrt{\Delta}=\sqrt{264}=\sqrt{4*66}=\sqrt{4}*\sqrt{66}=2\sqrt{66}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{66}}{2*-1}=\frac{-10-2\sqrt{66}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{66}}{2*-1}=\frac{-10+2\sqrt{66}}{-2}
$