A(x)=-11x^2-16x+20

Solution for A(x)=-11x^2-16x+20 equation:

(A)=-11A^2-16A+20

We move all terms to the left:

(A)-(-11A^2-16A+20)=0

We get rid of parentheses

11A^2+16A+A-20=0

We add all the numbers together, and all the variables

11A^2+17A-20=0

a = 11; b = 17; c = -20;
Δ = b2-4ac
Δ = 172-4·11·(-20)
Δ = 1169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(17)-\sqrt{1169}}{2*11}=\frac{-17-\sqrt{1169}}{22}
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(17)+\sqrt{1169}}{2*11}=\frac{-17+\sqrt{1169}}{22}
$