Y=1.2+x-0.025x^2

Solution for Y=1.2+x-0.025x^2 equation:

=1.2+Y-0.025Y^2

We move all terms to the left:

-(1.2+Y-0.025Y^2)=0

We get rid of parentheses

0.025Y^2-Y-1.2=0

We add all the numbers together, and all the variables

0.025Y^2-1Y-1.2=0

a = 0.025; b = -1; c = -1.2;
Δ = b2-4ac
Δ = -12-4·0.025·(-1.2)
Δ = 1.12
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{-(-1)-\sqrt{1.12}}{2*0.025}=\frac{1-\sqrt{1.12}}{0.05}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{1.12}}{2*0.025}=\frac{1+\sqrt{1.12}}{0.05}
$