The given equation models the maximum heart rate of a person:

Now.
a. Solve for A.
First, subtract both sides by 206.6

Then, divide both sides by -0.711

Simplify and get A:

b. According to this model, what is the age of an individual whose maximum heart rate is 163?
Now, we need to replace = 163

Hence, the individual would have an age of approximately 61 years.