0=4.9x^2+8x-1.8

Solution for 0=4.9x^2+8x-1.8 equation:

0=4.9x^2+8x-1.8

We move all terms to the left:

0-(4.9x^2+8x-1.8)=0

We add all the numbers together, and all the variables

-(4.9x^2+8x-1.8)=0

We get rid of parentheses

-4.9x^2-8x+1.8=0

a = -4.9; b = -8; c = +1.8;
Δ = b2-4ac
Δ = -82-4·(-4.9)·1.8
Δ = 99.28
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{99.28}}{2*-4.9}=\frac{8-\sqrt{99.28}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+\sqrt{99.28}}{2*-4.9}=\frac{8+\sqrt{99.28}}{-9.8}
$