(5n-6)(5n+1)=0

Solution for (5n-6)(5n+1)=0 equation:

(5n-6)(5n+1)=0

We multiply parentheses ..

(+25n^2+5n-30n-6)=0

We get rid of parentheses

25n^2+5n-30n-6=0

We add all the numbers together, and all the variables

25n^2-25n-6=0

a = 25; b = -25; c = -6;
Δ = b2-4ac
Δ = -252-4·25·(-6)
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-35}{2*25}=\frac{-10}{50}
=-1/5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+35}{2*25}=\frac{60}{50}
=1+1/5
$