3,2t-4,9t^2+3,45=0

Solution for 3,2t-4,9t^2+3,45=0 equation:

3.2t-4.9t^2+3.45=0

a = -4.9; b = 3.2; c = +3.45;
Δ = b2-4ac
Δ = 3.22-4·(-4.9)·3.45
Δ = 77.86
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{-(3.2)-\sqrt{77.86}}{2*-4.9}=\frac{-3.2-\sqrt{77.86}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3.2)+\sqrt{77.86}}{2*-4.9}=\frac{-3.2+\sqrt{77.86}}{-9.8}
$