We already have the equation that gives us the number of miles Johanna has left on her trip - it is the function f(x):
![f(x)=1084-65t](https://img.qammunity.org/2023/formulas/mathematics/college/rcr5xxyx2ecrvx3pfljvb6ffy94s331292.png)
where t is the number of hours of driving.
After 12 hours of driving, we have t = 12, putting that into f(x) gives
![f(12)=1084-65(12)](https://img.qammunity.org/2023/formulas/mathematics/college/nusbm1c2jvh92hmltg2wxbio90zc2qipnq.png)
![f(12)=304](https://img.qammunity.org/2023/formulas/mathematics/college/46c49bz3aca6awklcn1do2fbuztxoit107.png)
Hence, Johanna has left 304 miles after 12 hours of driving.