Medical researchers have determined that for exercise to be beneficial, a personâ€™s desirable heart rate, r, in beats per minute, can be approximated by the formulas r = 143 minus 0.65 a for women r = 165 minus 0.75 a for men, where a represents the personâ€™s age. if the desirable heart rate for a woman is 130 beats per minute, how old is she? a. 84 years old b. 57 years old c. 37 years old d. 20 years old
What are Linear Equation?