(2x+1)(-11-x)=0

Solution for (2x+1)(-11-x)=0 equation:

(2x+1)(-11-x)=0

We add all the numbers together, and all the variables

(2x+1)(-1x-11)=0

We multiply parentheses ..

(-2x^2-22x-1x-11)=0

We get rid of parentheses

-2x^2-22x-1x-11=0

We add all the numbers together, and all the variables

-2x^2-23x-11=0

a = -2; b = -23; c = -11;
Δ = b2-4ac
Δ = -232-4·(-2)·(-11)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-23)-21}{2*-2}=\frac{2}{-4}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-23)+21}{2*-2}=\frac{44}{-4}
=-11
$