We have to evaluate the piecewise function for f(6). This means when x=6.
Now, we have to look at the conditions.
So when x≥0, we use the second function.
So 6>0, then, we use the second function.
Then:
[tex]\begin{gathered} f(6)=7(6)+3 \\ f(6)=45 \end{gathered}[/tex]
Hence, the correct answer is option D.
