Math algebra help please

Question

the model m=-0.85a + 217 was developed by Miller to determine the maximum heart rate M of an individual who is age A.

a. Solve the model for A

b. According to this model what is the age of an individual whose maximum heart rate is 160??

Answer 1

m=-.85a +217

.85a = 217-m

a = (217-m)/.85

a = (217-160)/.85= 57/.85=5700/85= about 67.06

age = 67