0.1x^2-1.1x-1=0

Solution for 0.1x^2-1.1x-1=0 equation:

0.1x^2-1.1x-1=0

a = 0.1; b = -1.1; c = -1;
Δ = b2-4ac
Δ = -1.12-4·0.1·(-1)
Δ = 1.61
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{-(-1.1)-\sqrt{1.61}}{2*0.1}=\frac{1.1-\sqrt{1.61}}{0.2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.1)+\sqrt{1.61}}{2*0.1}=\frac{1.1+\sqrt{1.61}}{0.2}
$