Question 375697
1.) You have an inequality, NOT an equation,
2.) What is the question again?
Pulse Rate When you exercise, your pulse rate rises. Recommended pulse rates vary with age and physical condition. For vigorous exercise, such as jogging, the inequality: {{{0.7(220 - a) <= R <= 0.85(220 - a)}}} gives a target range for pulse rate R (in beats per minute), based on age a (in years). A. Substitute your age in the inequality above to find the range for your pulse rate when you are jogging. B. What is the target range for a person 25 years old? 

For A.) If a = 20 (just an example, not my real age),  {{{0.7(220 - 20) <= R <= 0.85(220- 20)}}}, or {{{140 <= R <= 170}}}.

for B.)  If a = 25, {{{0.7(220 - 25) <= R <= 0.85(220- 25)}}}, or {{{136.5 <= R <= 1165.75}}}.