we know that
the rate of a linear equation is equal to the slope
Step 1
Find the bear’s average heart rate when it’s active
Let
A(1.5,90) B ( 2,120)
the slope is equal to
m=(y2-y1)/(x2-x1)
m=(120-90)/(2-1.5)=30/0.5
m=60 heartbeats/min
therefore
the answer part a) is
the bear’s average heart rate when it’s active is 60 heartbeats/min
Step 2
Find the bear’s average heart rate when it’s hibernating
Let
A(1.5,18) B ( 2,24)
the slope is equal to
m=(y2-y1)/(x2-x1)
m=(24-18)/(2-1.5)=6/0.5
m=12 heartbeats/min
therefore
the answer part b) is
the bear’s average heart rate when it’s hibernating is 12 heartbeats/min