Question 134221
Remember, f(3) is asking "what is the value of f(x) (or y) when x=3?" 



Notice how the only inequality that has the value x=3 in the interval is the second equation {{{3x}}} since the inequality is {{{3<=x<=8}}}



So simply plug in x=3 into {{{3x}}}


{{{3(3)=9}}}



So {{{f(3)=9}}}