5n^2+80n+315=0

Solution for 5n^2+80n+315=0 equation:

5n^2+80n+315=0

a = 5; b = 80; c = +315;
Δ = b2-4ac
Δ = 802-4·5·315
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-10}{2*5}=\frac{-90}{10}
=-9
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+10}{2*5}=\frac{-70}{10}
=-7
$