0.1x^2-0.2x=3.5

Solution for 0.1x^2-0.2x=3.5 equation:

0.1x^2-0.2x=3.5

We move all terms to the left:

0.1x^2-0.2x-(3.5)=0

We add all the numbers together, and all the variables

0.1x^2-0.2x-3.5=0

a = 0.1; b = -0.2; c = -3.5;
Δ = b2-4ac
Δ = -0.22-4·0.1·(-3.5)
Δ = 1.44
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{-(-0.2)-\sqrt{1.44}}{2*0.1}=\frac{0.2-\sqrt{1.44}}{0.2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.2)+\sqrt{1.44}}{2*0.1}=\frac{0.2+\sqrt{1.44}}{0.2}
$