Answer:
y = 160 - 12x
Explanation:
Heart rate is initially at 160 and drops by 12 every minute. If x is the number of minutes then her heart beat reduces by 12x. This is subtracted from the initial rate of 160, for example
x = 1 : y = 160 - 12 = 148 ← after 1 minute
x = 2 : y = 160 - 24 = 136 ← after 2 minutes
x = 5 : y = 160 - 60 = 100 ← after 5 minutes