$7-10$ Use Stokes' Theorem to evaluate $\int_{C} \mathbf{F} \cdot d \mathbf{r} .$ In each case $C$ is
oriented counterclockwise as viewed from above.
$$\begin{array}{l}{\mathbf{F}(x, y, z)=x y \mathbf{i}+2 z \mathbf{j}+3 y \mathbf{k}, \quad C \text { is the curve of intersec- }} \\ {\text { tion of the plane } x+z=5 \text { and the cylinder } x^{2}+y^{2}=9}\end{array}$$