N=-0.14h^2+3h+5

Solution for N=-0.14h^2+3h+5 equation:

=-0.14N^2+3N+5

We move all terms to the left:

-(-0.14N^2+3N+5)=0

We get rid of parentheses

0.14N^2-3N-5=0

a = 0.14; b = -3; c = -5;
Δ = b2-4ac
Δ = -32-4·0.14·(-5)
Δ = 11.8
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$N_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$N_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$N_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-\sqrt{11.8}}{2*0.14}=\frac{3-\sqrt{11.8}}{0.28}
$
$N_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+\sqrt{11.8}}{2*0.14}=\frac{3+\sqrt{11.8}}{0.28}
$