4.9t^2-3t-1.40=0

Solution for 4.9t^2-3t-1.40=0 equation:

4.9t^2-3t-1.40=0

We add all the numbers together, and all the variables

4.9t^2-3t-1.4=0

a = 4.9; b = -3; c = -1.4;
Δ = b2-4ac
Δ = -32-4·4.9·(-1.4)
Δ = 36.44
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)-\sqrt{36.44}}{2*4.9}=\frac{3-\sqrt{36.44}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+\sqrt{36.44}}{2*4.9}=\frac{3+\sqrt{36.44}}{9.8}
$