I'm a high school senior interested in pursuing a major in quantitative economics, which I understand is heavily math-intensive. However, as it stands, my academic strengths are more verbal (780 on SAT) than mathematical (630 on SAT). Therefore, I'd much like to increase my skills at math and plan to devote a great deal of my summer studying from a precalculus textbook or two. That's where you good people at Math Stack Exchange come in. I'm hoping some of you could recommend a precalculus level textbook that has the potential to initiate a neophyte such as myself to the math world. Bonus points if you can recommend a textbook that somehow also has applications to economics.
By the way, I actually have already purchased a precalculus level textbook, the University of Chicago School Mathematics Project's Precalculus and Discrete Mathematics, but am of the understanding that it is more of a primer text and thus would be wisely supplemented by something a little more in-depth. This might be helpful to take into consideration as well. I asked this same question at Math Overflow and was told that the site is more reserved for research-level mathematics, and was referred here instead, so I hope this is the right domain for this sort of question. Many thanks for any and all replies.