Answer
a.$f(39)=25.5$, rounded to one decimal place,
b.$f(46)=24.2$, rounded to one decimal places.
Work Step by Step
$x=2008-1969=39$,
$f(x)=-7.52\ln{x}+53$,
a. $f(39)=-7.52\ln{39}+53$,
$f(39)=25.45$,
$f(39)=25.5$, rounded to one decimal place,
The result found by the function undersetimates the actual data of $26.2$ in the graph by $0.7$.
b. $x=2015-1969=46$,
$f(46)=-7.52\ln{46}+53$,
$f(46)=24.21$,
$f(46)=24.2$, rounded to one decimal places.