0=4.9x^2+4x

Solution for 0=4.9x^2+4x equation:

0=4.9x^2+4x

We move all terms to the left:

0-(4.9x^2+4x)=0

We add all the numbers together, and all the variables

-(4.9x^2+4x)=0

We get rid of parentheses

-4.9x^2-4x=0

a = -4.9; b = -4; c = 0;
Δ = b2-4ac
Δ = -42-4·(-4.9)·0
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-4}{2*-4.9}=\frac{0}{-9.8}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+4}{2*-4.9}=\frac{8}{-9.8}
=-8/9.8
$