For this case we have a function of the form:

Where,
A: initial value of an autographed baseball
b: growth rate
x: number of years
Substituting values we have:

For the moment when the value is at least 650 $ we have the following inequality:

Answer:
a one-variable inequality that could be used to solve for the number of years, x, it would take for the baseball to be worth at least $650 is:
