0=-4.9x^2+10.0x+100

Solution for 0=-4.9x^2+10.0x+100 equation:

0=-4.9x^2+10.0x+100

We move all terms to the left:

0-(-4.9x^2+10.0x+100)=0

We add all the numbers together, and all the variables

-(-4.9x^2+10.0x+100)=0

We get rid of parentheses

4.9x^2-10.0x-100=0

We add all the numbers together, and all the variables

4.9x^2-10x-100=0

a = 4.9; b = -10; c = -100;
Δ = b2-4ac
Δ = -102-4·4.9·(-100)
Δ = 2060
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:

$\sqrt{\Delta}=\sqrt{2060}=\sqrt{4*515}=\sqrt{4}*\sqrt{515}=2\sqrt{515}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{515}}{2*4.9}=\frac{10-2\sqrt{515}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{515}}{2*4.9}=\frac{10+2\sqrt{515}}{9.8}
$