Y=0.2x2-0.2x-2.4

Solution for Y=0.2x2-0.2x-2.4 equation:

=0.2Y^2-0.2Y-2.4

We move all terms to the left:

-(0.2Y^2-0.2Y-2.4)=0

We get rid of parentheses

-0.2Y^2+0.2Y+2.4=0

a = -0.2; b = 0.2; c = +2.4;
Δ = b2-4ac
Δ = 0.22-4·(-0.2)·2.4
Δ = 1.96
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0.2)-\sqrt{1.96}}{2*-0.2}=\frac{-0.2-\sqrt{1.96}}{-0.4}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.2)+\sqrt{1.96}}{2*-0.2}=\frac{-0.2+\sqrt{1.96}}{-0.4}
$