(x+16)(x+16)=400

Solution for (x+16)(x+16)=400 equation:

(x+16)(x+16)=400

We move all terms to the left:

(x+16)(x+16)-(400)=0

We multiply parentheses ..

(+x^2+16x+16x+256)-400=0

We get rid of parentheses

x^2+16x+16x+256-400=0

We add all the numbers together, and all the variables

x^2+32x-144=0

a = 1; b = 32; c = -144;
Δ = b2-4ac
Δ = 322-4·1·(-144)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(32)-40}{2*1}=\frac{-72}{2}
=-36
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(32)+40}{2*1}=\frac{8}{2}
=4
$