0=-4.9x^2+8x+12

Solution for 0=-4.9x^2+8x+12 equation:

0=-4.9x^2+8x+12

We move all terms to the left:

0-(-4.9x^2+8x+12)=0

We add all the numbers together, and all the variables

-(-4.9x^2+8x+12)=0

We get rid of parentheses

4.9x^2-8x-12=0

a = 4.9; b = -8; c = -12;
Δ = b2-4ac
Δ = -82-4·4.9·(-12)
Δ = 299.2
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{-(-8)-\sqrt{299.2}}{2*4.9}=\frac{8-\sqrt{299.2}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+\sqrt{299.2}}{2*4.9}=\frac{8+\sqrt{299.2}}{9.8}
$