11=-4.5x+4.905x^2

Solution for 11=-4.5x+4.905x^2 equation:

11=-4.5x+4.905x^2

We move all terms to the left:

11-(-4.5x+4.905x^2)=0

We get rid of parentheses

-4.905x^2+4.5x+11=0

a = -4.905; b = 4.5; c = +11;
Δ = b2-4ac
Δ = 4.52-4·(-4.905)·11
Δ = 236.07
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{-(4.5)-\sqrt{236.07}}{2*-4.905}=\frac{-4.5-\sqrt{236.07}}{-9.81}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4.5)+\sqrt{236.07}}{2*-4.905}=\frac{-4.5+\sqrt{236.07}}{-9.81}
$