0=4.9x^2-12x-80

Solution for 0=4.9x^2-12x-80 equation:

0=4.9x^2-12x-80

We move all terms to the left:

0-(4.9x^2-12x-80)=0

We add all the numbers together, and all the variables

-(4.9x^2-12x-80)=0

We get rid of parentheses

-4.9x^2+12x+80=0

a = -4.9; b = 12; c = +80;
Δ = b2-4ac
Δ = 122-4·(-4.9)·80
Δ = 1712
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:

$\sqrt{\Delta}=\sqrt{1712}=\sqrt{16*107}=\sqrt{16}*\sqrt{107}=4\sqrt{107}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-4\sqrt{107}}{2*-4.9}=\frac{-12-4\sqrt{107}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+4\sqrt{107}}{2*-4.9}=\frac{-12+4\sqrt{107}}{-9.8}
$