(6d-9)(d+12)=0

Solution for (6d-9)(d+12)=0 equation:

(6d-9)(d+12)=0

We multiply parentheses ..

(+6d^2+72d-9d-108)=0

We get rid of parentheses

6d^2+72d-9d-108=0

We add all the numbers together, and all the variables

6d^2+63d-108=0

a = 6; b = 63; c = -108;
Δ = b2-4ac
Δ = 632-4·6·(-108)
Δ = 6561
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6561}=81$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(63)-81}{2*6}=\frac{-144}{12}
=-12
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(63)+81}{2*6}=\frac{18}{12}
=1+1/2
$