SAT Level 4 Passport to Advanced Math Problem with Solution Today I would like to solve the last SAT math problem I posted. You can see the original post here: SAT Level 4 Passport to Advanced Math Problem Level 4 Passport to Advanced Math Let m = 2x + 7 and k = 2x – 7, and write km = cx2 + d, where c and d are constants. What is the value of c – d ? * Solution using the difference of two squares: km = (2x + 7)(2x – 7) = 4x2 – 49. So, we have 4x2 – 49 = cx2 + d. Thus, c = 4 and d = –49. It follows that c – d = 4 – (–49) = 4 + 49 = 53. Share this problem with your Facebook friends that are preparing for the SAT If you’re preparing for the SAT, you may want to check out the Get 800 collection of SAT math books. Comments comments