Y=0.8x+-0.0267x2

Solution for Y=0.8x+-0.0267x2 equation:

=0.8Y+-0.0267Y^2

We move all terms to the left:

-(0.8Y+-0.0267Y^2)=0

We use the square of the difference formula

-(0.8Y-0.0267Y^2)=0

We get rid of parentheses

0.0267Y^2-0.8Y=0

a = 0.0267; b = -0.8; c = 0;
Δ = b2-4ac
Δ = -0.82-4·0.0267·0
Δ = 0.64
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{-(-0.8)-\sqrt{0.64}}{2*0.0267}=\frac{0.8-\sqrt{0.64}}{0.0534}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.8)+\sqrt{0.64}}{2*0.0267}=\frac{0.8+\sqrt{0.64}}{0.0534}
$