x=-4.9x^2

Solution for x=-4.9x^2 equation:

x=-4.9x^2

We move all terms to the left:

x-(-4.9x^2)=0

We get rid of parentheses

4.9x^2+x=0

a = 4.9; b = 1; c = 0;
Δ = b2-4ac
Δ = 12-4·4.9·0
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

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