0=19.28x-4.9x^2

Solution for 0=19.28x-4.9x^2 equation:

0=19.28x-4.9x^2

We move all terms to the left:

0-(19.28x-4.9x^2)=0

We add all the numbers together, and all the variables

-(19.28x-4.9x^2)=0

We get rid of parentheses

4.9x^2-19.28x=0

a = 4.9; b = -19.28; c = 0;
Δ = b2-4ac
Δ = -19.282-4·4.9·0
Δ = 371.7184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-19.28)-\sqrt{371.7184}}{2*4.9}=\frac{19.28-\sqrt{371.7184}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-19.28)+\sqrt{371.7184}}{2*4.9}=\frac{19.28+\sqrt{371.7184}}{9.8}
$