Jefferson High School is planning to expand its student parking lot by expanding the existing lot as shown.
The size of the new parking lot will be twice the old lot. In how many feet, x, was the old lot expanded by? In this problem, the x's are the same.

(The picture will not load, so a brief explanation. The picture shows one large rectangle; and inside is one smaller rectangle [school, with the measurements of 165 ft. wide by 300 ft. long], and two L shapes. One L shape is the [old lot, measured 75 ft wider on top of the school width and 75 ft longer on top of the length], and the other L shape is unmarked.)