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

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

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

We multiply parentheses ..

(+18n^2+30n+15n+25)=0

We get rid of parentheses

18n^2+30n+15n+25=0

We add all the numbers together, and all the variables

18n^2+45n+25=0

a = 18; b = 45; c = +25;
Δ = b2-4ac
Δ = 452-4·18·25
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-15}{2*18}=\frac{-60}{36}
=-1+2/3
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+15}{2*18}=\frac{-30}{36}
=-5/6
$