33=35t-4.9t^2

Solution for 33=35t-4.9t^2 equation:

33=35t-4.9t^2

We move all terms to the left:

33-(35t-4.9t^2)=0

We get rid of parentheses

4.9t^2-35t+33=0

a = 4.9; b = -35; c = +33;
Δ = b2-4ac
Δ = -352-4·4.9·33
Δ = 578.2
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{-(-35)-\sqrt{578.2}}{2*4.9}=\frac{35-\sqrt{578.2}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-35)+\sqrt{578.2}}{2*4.9}=\frac{35+\sqrt{578.2}}{9.8}
$