0.1x^2-x-18=0

Solution for 0.1x^2-x-18=0 equation:

0.1x^2-x-18=0

We add all the numbers together, and all the variables

0.1x^2-1x-18=0

a = 0.1; b = -1; c = -18;
Δ = b2-4ac
Δ = -12-4·0.1·(-18)
Δ = 8.2
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{-(-1)-\sqrt{8.2}}{2*0.1}=\frac{1-\sqrt{8.2}}{0.2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{8.2}}{2*0.1}=\frac{1+\sqrt{8.2}}{0.2}
$