Y=0.1x^2-2x

Solution for Y=0.1x^2-2x equation:

=0.1Y^2-2Y

We move all terms to the left:

-(0.1Y^2-2Y)=0

We get rid of parentheses

-0.1Y^2+2Y=0

a = -0.1; b = 2; c = 0;
Δ = b2-4ac
Δ = 22-4·(-0.1)·0
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2}{2*-0.1}=\frac{-4}{-0.2}
=+20
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2}{2*-0.1}=\frac{0}{-0.2}
=0
$