12.5#2

I have redone this problem about 5 times now and it is very tedious. I don't know what I'm doing wrong. I will email you my work!

***********************************

The only flaw here is in your execution rather than your understanding. It's minor but keeps you from a correct answer. From one line to the next you consistently skip writing down a few steps which you've done in your head. Since you and I and everybody get slightly blurry about what's in our own heads, this leads to "minor" mistakes such as missing a few minus signs, but these mistakes get amplified by the time you've gone a few more steps until your answer can be far from correct.  My personal method, after many long involved calculations is to take the space to write *EVERY* single step down.  You may want to try this also.