(x+8)(x+8)-9=0

Solution for (x+8)(x+8)-9=0 equation:

(x+8)(x+8)-9=0

We multiply parentheses ..

(+x^2+8x+8x+64)-9=0

We get rid of parentheses

x^2+8x+8x+64-9=0

We add all the numbers together, and all the variables

x^2+16x+55=0

a = 1; b = 16; c = +55;
Δ = b2-4ac
Δ = 162-4·1·55
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-6}{2*1}=\frac{-22}{2}
=-11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+6}{2*1}=\frac{-10}{2}
=-5
$