0=4.9x^2+6x-100

Solution for 0=4.9x^2+6x-100 equation:

0=4.9x^2+6x-100

We move all terms to the left:

0-(4.9x^2+6x-100)=0

We add all the numbers together, and all the variables

-(4.9x^2+6x-100)=0

We get rid of parentheses

-4.9x^2-6x+100=0

a = -4.9; b = -6; c = +100;
Δ = b2-4ac
Δ = -62-4·(-4.9)·100
Δ = 1996
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1996}=\sqrt{4*499}=\sqrt{4}*\sqrt{499}=2\sqrt{499}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{499}}{2*-4.9}=\frac{6-2\sqrt{499}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{499}}{2*-4.9}=\frac{6+2\sqrt{499}}{-9.8}
$