0=-4.9x^2+4x+79.2

Solution for 0=-4.9x^2+4x+79.2 equation:

0=-4.9x^2+4x+79.2

We move all terms to the left:

0-(-4.9x^2+4x+79.2)=0

We add all the numbers together, and all the variables

-(-4.9x^2+4x+79.2)=0

We get rid of parentheses

4.9x^2-4x-79.2=0

a = 4.9; b = -4; c = -79.2;
Δ = b2-4ac
Δ = -42-4·4.9·(-79.2)
Δ = 1568.32
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-\sqrt{1568.32}}{2*4.9}=\frac{4-\sqrt{1568.32}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+\sqrt{1568.32}}{2*4.9}=\frac{4+\sqrt{1568.32}}{9.8}
$