3. Then she needs to find her "heart rate reserve" h by subtracting her average resting heart rate R from her maximum heart rate m. Write an equation she can use

F(x) = x2 − 9, and g(x) = x − 3 f(x) = x2 − 4x + 3, and g(x) = x − 3 f(x) = x2 + 4x − 5, and g(x) = x − 1 f(x) = x2 − 16, and g(x) = x − 4 h(x) = x + 5 arrowright h(x) = x + 3 arrowright h(x) = x + 4 arrowright h(x) = x − 1 arrowright

Combine the information in the problem and the chart using the average balance method to solve the problem.

Which of the following contains a variable?