(5n+3)(-4n-6)=0

Solution for (5n+3)(-4n-6)=0 equation:

(5n+3)(-4n-6)=0

We multiply parentheses ..

(-20n^2-30n-12n-18)=0

We get rid of parentheses

-20n^2-30n-12n-18=0

We add all the numbers together, and all the variables

-20n^2-42n-18=0

a = -20; b = -42; c = -18;
Δ = b2-4ac
Δ = -422-4·(-20)·(-18)
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-42)-18}{2*-20}=\frac{24}{-40}
=-3/5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-42)+18}{2*-20}=\frac{60}{-40}
=-1+1/2
$