by danc Fri Nov 28, 2014 2:50 pm
There is a typo in that line that might be confusing. When they plug in 3C for V the "close parenthesis" is in the wrong place. It should read 2(3C)—360=3C. After that, everything follows normally and the answer is correct. But, with the parenthesis where they are in the book, 2(3C—360)=3C, you'd have to distribute the multiplication by 2 to the 360 as well leaving you with 6C—720=3C, which would yield the wrong answer.