11-x(x-3)=-81

Solution for 11-x(x-3)=-81 equation:

11-x(x-3)=-81

We move all terms to the left:

11-x(x-3)-(-81)=0

We add all the numbers together, and all the variables

-x(x-3)+92=0

We multiply parentheses

-x^2+3x+92=0

We add all the numbers together, and all the variables

-1x^2+3x+92=0

a = -1; b = 3; c = +92;
Δ = b2-4ac
Δ = 32-4·(-1)·92
Δ = 377
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-\sqrt{377}}{2*-1}=\frac{-3-\sqrt{377}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{377}}{2*-1}=\frac{-3+\sqrt{377}}{-2}
$