(f+11)(f-10)=0

Solution for (f+11)(f-10)=0 equation:

(f+11)(f-10)=0

We multiply parentheses ..

(+f^2-10f+11f-110)=0

We get rid of parentheses

f^2-10f+11f-110=0

We add all the numbers together, and all the variables

f^2+f-110=0

a = 1; b = 1; c = -110;
Δ = b2-4ac
Δ = 12-4·1·(-110)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-21}{2*1}=\frac{-22}{2}
=-11
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+21}{2*1}=\frac{20}{2}
=10
$