(-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+21x-11=0

a = 2; b = 21; c = -11;
Δ = b2-4ac
Δ = 212-4·2·(-11)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-23}{2*2}=\frac{-44}{4}
=-11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+23}{2*2}=\frac{2}{4}
=1/2
$