-450=-4.9t^2-5t

Solution for -450=-4.9t^2-5t equation:

-450=-4.9t^2-5t

We move all terms to the left:

-450-(-4.9t^2-5t)=0

We get rid of parentheses

4.9t^2+5t-450=0

a = 4.9; b = 5; c = -450;
Δ = b2-4ac
Δ = 52-4·4.9·(-450)
Δ = 8845
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{8845}}{2*4.9}=\frac{-5-\sqrt{8845}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{8845}}{2*4.9}=\frac{-5+\sqrt{8845}}{9.8}
$