0=35x-4.9x^2

Solution for 0=35x-4.9x^2 equation:

0=35x-4.9x^2

We move all terms to the left:

0-(35x-4.9x^2)=0

We add all the numbers together, and all the variables

-(35x-4.9x^2)=0

We get rid of parentheses

4.9x^2-35x=0

a = 4.9; b = -35; c = 0;
Δ = b2-4ac
Δ = -352-4·4.9·0
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-35)-35}{2*4.9}=\frac{0}{9.8}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-35)+35}{2*4.9}=\frac{70}{9.8}
=7+1/7
$