-1.95=4.4*t-4.905*t^2

Solution for -1.95=4.4*t-4.905*t^2 equation:

-1.95=4.4*t-4.905*t^2

We move all terms to the left:

-1.95-(4.4*t-4.905*t^2)=0

We get rid of parentheses

-4.4*t+4.905*t^2-1.95=0

We add all the numbers together, and all the variables

4.905t^2-4.4t-1.95=0

a = 4.905; b = -4.4; c = -1.95;
Δ = b2-4ac
Δ = -4.42-4·4.905·(-1.95)
Δ = 57.619
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{-(-4.4)-\sqrt{57.619}}{2*4.905}=\frac{4.4-\sqrt{57.619}}{9.81}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.4)+\sqrt{57.619}}{2*4.905}=\frac{4.4+\sqrt{57.619}}{9.81}
$