Answer
a.$f(39)=14.8$, rounded to one decimal place,
b.$f(46)=14.1$, rounded to one decimal places.
Work Step by Step
$x=2008-1969=39$,
$f(x)=-4.82\ln{x}+32.5$,
a. $f(39)=-4.82\ln{39}+32.5$,
$f(39)=14.84$,
$f(39)=14.8$, rounded to one decimal place,
The result found by the function underestimates the actual data of $15.5$ in the graph by $0.7$.
b. $x=2015-1969=46$,
$f(46)=-4.82\ln{46}+32.5$,
$f(46)=14.05$,
$f(46)=14.1$, rounded to one decimal places.