n^2+70n-28500=0

Solution for n^2+70n-28500=0 equation:

n^2+70n-28500=0

a = 1; b = 70; c = -28500;
Δ = b2-4ac
Δ = 702-4·1·(-28500)
Δ = 118900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{118900}=\sqrt{100*1189}=\sqrt{100}*\sqrt{1189}=10\sqrt{1189}$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(70)-10\sqrt{1189}}{2*1}=\frac{-70-10\sqrt{1189}}{2}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(70)+10\sqrt{1189}}{2*1}=\frac{-70+10\sqrt{1189}}{2}
$