Y=-4.9t^2+100t-392

Solution for Y=-4.9t^2+100t-392 equation:

=-4.9Y^2+100Y-392

We move all terms to the left:

-(-4.9Y^2+100Y-392)=0

We get rid of parentheses

4.9Y^2-100Y+392=0

a = 4.9; b = -100; c = +392;
Δ = b2-4ac
Δ = -1002-4·4.9·392
Δ = 2316.8
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-100)-\sqrt{2316.8}}{2*4.9}=\frac{100-\sqrt{2316.8}}{9.8}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-100)+\sqrt{2316.8}}{2*4.9}=\frac{100+\sqrt{2316.8}}{9.8}
$