(5d-5)(d+11)=0

Solution for (5d-5)(d+11)=0 equation:

(5d-5)(d+11)=0

We multiply parentheses ..

(+5d^2+55d-5d-55)=0

We get rid of parentheses

5d^2+55d-5d-55=0

We add all the numbers together, and all the variables

5d^2+50d-55=0

a = 5; b = 50; c = -55;
Δ = b2-4ac
Δ = 502-4·5·(-55)
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-60}{2*5}=\frac{-110}{10}
=-11
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+60}{2*5}=\frac{10}{10}
=1
$