50=0.0515(x)^2+1.1(x)

Solution for 50=0.0515(x)^2+1.1(x) equation:

50=0.0515(x)^2+1.1(x)

We move all terms to the left:

50-(0.0515(x)^2+1.1(x))=0

We get rid of parentheses

-0.0515x^2-1.1x+50=0

a = -0.0515; b = -1.1; c = +50;
Δ = b2-4ac
Δ = -1.12-4·(-0.0515)·50
Δ = 11.51
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{-(-1.1)-\sqrt{11.51}}{2*-0.0515}=\frac{1.1-\sqrt{11.51}}{-0.103}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.1)+\sqrt{11.51}}{2*-0.0515}=\frac{1.1+\sqrt{11.51}}{-0.103}
$