4.9t^2+25t=10.2

Solution for 4.9t^2+25t=10.2 equation:

4.9t^2+25t=10.2

We move all terms to the left:

4.9t^2+25t-(10.2)=0

We add all the numbers together, and all the variables

4.9t^2+25t-10.2=0

a = 4.9; b = 25; c = -10.2;
Δ = b2-4ac
Δ = 252-4·4.9·(-10.2)
Δ = 824.92
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{-(25)-\sqrt{824.92}}{2*4.9}=\frac{-25-\sqrt{824.92}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+\sqrt{824.92}}{2*4.9}=\frac{-25+\sqrt{824.92}}{9.8}
$