Answer:
To solve the equation f(x) = 3, we can set the expression for f(x) equal to 3 and then solve for x. In other words, we want to find the values of x that make the equation 5 - \frac{x}{r^2} + 5 + 6 = 3 true.
We can start by simplifying the left side of the equation by combining like terms. This gives us
5 - \frac{x}{r^2} + 5 + 6 = 5 + 5 - \frac{x}{r^2} + 6 = 10 - \frac{x}{r^2} + 6
Next, we set this expression equal to 3 and solve for x:
10 - \frac{x}{r^2} + 6 = 3 \quad \Rightarrow \quad 10 - 6 = 3 - \frac{x}{r^2} \quad \Rightarrow \quad \frac{x}{r^2} = 7
To solve for x, we can multiply both sides of the equation by r^2:
x = 7r^2
Therefore, the solutions to the equation f(x) = 3 are $x = 7r^2$. Note that this is a general solution, and it may not give all the possible values of $x$ that make the equation true. It's also possible that there are no solutions, depending on the value of $r$.