We are given the following functions:
![\begin{gathered} q(x)=x^2+6 \\ r(x)=\sqrt[]{x+9} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4v03w0yraan2le3qj9czbtqp76u5tja47y.png)
We are asked to determine the following composition of functions:
![r\circ q](https://img.qammunity.org/2023/formulas/mathematics/college/9n2uuh1y4lfkg49az46d99ibsunvdbdyay.png)
This composition is equivalent to the following:
![r\circ q=r(q(x))](https://img.qammunity.org/2023/formulas/mathematics/college/pco69ih6ghme0jj60uteqlxhz6gjvgpl5c.png)
This means that we will substitute the function q(x) for the value of "x" in the function r(x), like this:
![r(q(x))=\sqrt[]{(x^2+6)+9}](https://img.qammunity.org/2023/formulas/mathematics/college/ukbnt5yjwf40br1srg0zw05ijqzrcnaw2t.png)
Now, we add like terms:
![r(q(x))=\sqrt[]{x^2+15}](https://img.qammunity.org/2023/formulas/mathematics/college/a0xxo5iuca74k9nx6rfep1fo4tku4i4dth.png)
Now, since we are asked about the composition when x = 7 we will substitute the values of "x = 7" in the resulting function:
![r(q(7))=\sqrt[]{(7)^2+15}](https://img.qammunity.org/2023/formulas/mathematics/college/s5nib6q9iw5o9o5f79qqm2se0he7016ndc.png)
Now, we solve the operations:
![r(q(7))=8](https://img.qammunity.org/2023/formulas/mathematics/college/ey2m7f8in3lwklu7oniarvuexaxv98larq.png)
Therefore, the value of the composition of function at "x = 7" is 8. We can use the same procedure to determine the composition of q and r.