The median home price in the United States over the period 2003-2011 can be approximated by P(t) = −5t2 + 75t − 30 thousand dollars (3 ≤ t ≤ 11), where t is time in years since the start of 2000.† 
Find P'(t) and P'(7).
P'(t)	=
P'(7)	=
What does the answer tell you about home prices? HINT [See Example 2.] 
The median price of a home was  increasing at a rate of $ ___ per year in   ____.