0=4.9x^2-2.3x-0.15

Solution for 0=4.9x^2-2.3x-0.15 equation:

0=4.9x^2-2.3x-0.15

We move all terms to the left:

0-(4.9x^2-2.3x-0.15)=0

We add all the numbers together, and all the variables

-(4.9x^2-2.3x-0.15)=0

We get rid of parentheses

-4.9x^2+2.3x+0.15=0

a = -4.9; b = 2.3; c = +0.15;
Δ = b2-4ac
Δ = 2.32-4·(-4.9)·0.15
Δ = 8.23
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{-(2.3)-\sqrt{8.23}}{2*-4.9}=\frac{-2.3-\sqrt{8.23}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.3)+\sqrt{8.23}}{2*-4.9}=\frac{-2.3+\sqrt{8.23}}{-9.8}
$