Y=3x^2+9.1x

Solution for Y=3x^2+9.1x equation:

=3Y^2+9.1Y

We move all terms to the left:

-(3Y^2+9.1Y)=0

We get rid of parentheses

-3Y^2-9.1Y=0

a = -3; b = -9.1; c = 0;
Δ = b2-4ac
Δ = -9.12-4·(-3)·0
Δ = 82.81
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{-(-9.1)-\sqrt{82.81}}{2*-3}=\frac{9.1-\sqrt{82.81}}{-6}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9.1)+\sqrt{82.81}}{2*-3}=\frac{9.1+\sqrt{82.81}}{-6}
$