0=-4.9x^2+8.6x+3

Solution for 0=-4.9x^2+8.6x+3 equation:

0=-4.9x^2+8.6x+3

We move all terms to the left:

0-(-4.9x^2+8.6x+3)=0

We add all the numbers together, and all the variables

-(-4.9x^2+8.6x+3)=0

We get rid of parentheses

4.9x^2-8.6x-3=0

a = 4.9; b = -8.6; c = -3;
Δ = b2-4ac
Δ = -8.62-4·4.9·(-3)
Δ = 132.76
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{-(-8.6)-\sqrt{132.76}}{2*4.9}=\frac{8.6-\sqrt{132.76}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8.6)+\sqrt{132.76}}{2*4.9}=\frac{8.6+\sqrt{132.76}}{9.8}
$