-28n^2+100n+200=0

Solution for -28n^2+100n+200=0 equation:

-28n^2+100n+200=0

a = -28; b = 100; c = +200;
Δ = b2-4ac
Δ = 1002-4·(-28)·200
Δ = 32400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{32400}=180$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-180}{2*-28}=\frac{-280}{-56}
=+5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+180}{2*-28}=\frac{80}{-56}
=-1+3/7
$