0=-735-73.783t+4.905t^2

Solution for 0=-735-73.783t+4.905t^2 equation:

0=-735-73.783t+4.905t^2

We move all terms to the left:

0-(-735-73.783t+4.905t^2)=0

We add all the numbers together, and all the variables

-(-735-73.783t+4.905t^2)=0

We get rid of parentheses

-4.905t^2+73.783t+735=0

a = -4.905; b = 73.783; c = +735;
Δ = b2-4ac
Δ = 73.7832-4·(-4.905)·735
Δ = 19864.631089
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{-(73.783)-\sqrt{19864.631089}}{2*-4.905}=\frac{-73.783-\sqrt{19864.631089}}{-9.81}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(73.783)+\sqrt{19864.631089}}{2*-4.905}=\frac{-73.783+\sqrt{19864.631089}}{-9.81}
$