Answer
a) \$52,000
b) \$52,723; only \$723 off the estimate in part a, which could be considered an accurate model
c) \$52,628; only $628 off the estimate in part a, which is a more accurate model than the previous one, but both models represent the estimate well
Work Step by Step
a) Looking at the graph, what cost \$10,000 in 1967 would cost about \$52,000 in 2000. This is accurate since the point on the graph is just over the \$50,000 mark and definitely under the \$55,000 mark.
b) Since $x$ represents the number of years after 1980, plug 20 into $x$ to find the cost in 2000 of what cost \$10,000 in 1967. $C=1388(20)+24,963=52,723$
c) Since $x$ represents the number of years after 1980, plug 20 into $x$ to find the cost in 2000 of what cost \$10,000 in 1967. $C=3(20)^{2}+1308(20)+25,268=52,628$
