This would simplify to 6.60 meters/second.
The rate of change of Pete's height from 3 to 5 years can be determined as,

Thus, the required rate of change from 3 to 5 years is 4 in/year.
The answer is 2 ( choose 2 )
and how we find this answer? the picture is clearly for that.
Let m be the slope:
m=(y₂-y₁)/(x₂-x₁)
solve for c:
1/6=(9-c)/(1-7)
1/6=(9-c)/-6
-1=9-c
-10=-c
c=10