11=-3x+4.905x^2

Solution for 11=-3x+4.905x^2 equation:

11=-3x+4.905x^2

We move all terms to the left:

11-(-3x+4.905x^2)=0

We get rid of parentheses

-4.905x^2+3x+11=0

a = -4.905; b = 3; c = +11;
Δ = b2-4ac
Δ = 32-4·(-4.905)·11
Δ = 224.82
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-\sqrt{224.82}}{2*-4.905}=\frac{-3-\sqrt{224.82}}{-9.81}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{224.82}}{2*-4.905}=\frac{-3+\sqrt{224.82}}{-9.81}
$