So starting with the x variable:
Using the vertical angles theorem, we can make the equation
![15x-44=91](https://img.qammunity.org/2019/formulas/mathematics/middle-school/xiu8m7hi4myftvto2dw615n8h69cgccdl5.png)
and solve from there.
Add 44 on each side to get
![15x=135](https://img.qammunity.org/2019/formulas/mathematics/middle-school/rcq60b8x01f0la9xx7vr1lg8n3g23zlu7q.png)
Divide 15 on each side to get
![x=9](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ezy49ncjj6m8dvz4krr9ok07ir3u3k8oz9.png)
Next with the Z variable:
Using the linear pair theorem, we can make the equation
![91+z=180](https://img.qammunity.org/2019/formulas/mathematics/middle-school/7d2r74629nbrjjs2f1til6lp6gd5lifn78.png)
and solve.
Just subtract 91 on each side to get
![z=89](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ju7f4jdex5fyz915k7zmxex0v7usjqmnq3.png)
.