jmc

We can arrange the books on the shelf, pretending that the two math books are actually one book because they must be next to each other. In exactly half of these arrangements, the math books will be to the left of the physics book, giving $6!/2=360$ arrangements. However, in each of these arrangements there are two ways to arrange the math books, so the total number of arrangements is $360\cdot 2=\boxed{720}$.