Answer :
[tex]f(x)=2x[/tex]
If f(x) = 29:
[tex]\begin{gathered} f(x)=29 \\ 29=2x \end{gathered}[/tex]Solve for x:
Divide both sides by 2:
[tex]\begin{gathered} \frac{29}{2}=\frac{2x}{2} \\ x=\frac{29}{2} \\ x=14.5 \end{gathered}[/tex]