-0.25=2.37t-4.9t^2

Solution for -0.25=2.37t-4.9t^2 equation:

-0.25=2.37t-4.9t^2

We move all terms to the left:

-0.25-(2.37t-4.9t^2)=0

We get rid of parentheses

4.9t^2-2.37t-0.25=0

a = 4.9; b = -2.37; c = -0.25;
Δ = b2-4ac
Δ = -2.372-4·4.9·(-0.25)
Δ = 10.5169
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{-(-2.37)-\sqrt{10.5169}}{2*4.9}=\frac{2.37-\sqrt{10.5169}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.37)+\sqrt{10.5169}}{2*4.9}=\frac{2.37+\sqrt{10.5169}}{9.8}
$