The compositions of functions can be understood as:
![(f\circ g)(x)=f(g(x))](https://img.qammunity.org/2023/formulas/mathematics/college/qytlfzimoxtv7qpo9rm3ru8joolfgz0nxs.png)
it means that we insert the value of x, in the second function.
means that we look at the graph x=4,
at x=4, g(x) is equal to 3. this means that it can be reduced to
![\begin{gathered} (f\circ g)(4)=f(g(4)) \\ \text{and, } \\ g(4)=3 \\ \text{reduced to} \\ f(3) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/peewkus8x22nm3amapw4bcg19bj6cpna4e.png)
finally, looking at f(x), at x=3 we can see that
![\begin{gathered} f(3)=3 \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7hbcokq9dpmy3d795qv48zijuq20u4d1q5.png)
then:
![(f\circ g)(4)=f(g(4))=3](https://img.qammunity.org/2023/formulas/mathematics/college/smax9lg6zx6gsr3fxsk8ilo729437vbgfk.png)