-8x(x+16)-11(x+16)=0

Solution for -8x(x+16)-11(x+16)=0 equation:

-8x(x+16)-11(x+16)=0

We multiply parentheses

-8x^2-128x-11x-176=0

We add all the numbers together, and all the variables

-8x^2-139x-176=0

a = -8; b = -139; c = -176;
Δ = b2-4ac
Δ = -1392-4·(-8)·(-176)
Δ = 13689
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{13689}=117$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-139)-117}{2*-8}=\frac{22}{-16}
=-1+3/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-139)+117}{2*-8}=\frac{256}{-16}
=-16
$