t=-4.9t^2+6.5t+2.0

Solution for t=-4.9t^2+6.5t+2.0 equation:

t=-4.9t^2+6.5t+2.0

We move all terms to the left:

t-(-4.9t^2+6.5t+2.0)=0

We get rid of parentheses

4.9t^2-6.5t+t-2.0=0

We add all the numbers together, and all the variables

4.9t^2-5.5t-2=0

a = 4.9; b = -5.5; c = -2;
Δ = b2-4ac
Δ = -5.52-4·4.9·(-2)
Δ = 69.45
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{-(-5.5)-\sqrt{69.45}}{2*4.9}=\frac{5.5-\sqrt{69.45}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5.5)+\sqrt{69.45}}{2*4.9}=\frac{5.5+\sqrt{69.45}}{9.8}
$