Hello, I'm going through a "self-teaching" algebra book and am surprised at how much of it I remember. Throughout the book they have several quick-check tests. I've been a little confused as to the answer they put in the book compared with mine. Here are two examples:
1:Combine Like Terms: 2k-3ab+4-y+7ab-ab My answer was this: 2k+3ab+4-y The book answer was: 3ab+2k-y+4
2:Subtract Horizontally: 4n+2k-3m from 8n-5k-m My answer was this: -7k+2m+4n The book answer was: +4n-7k+2m
My confusion comes from the contrast in the book answers. In problem #1, the book seems to use alphabetical order of the literal factors (ab, then k, then y). However, in problem #2, the answer has the literal factors out of order, whereas my answer for #2 did have them in alphabetical order. Are my answers correct? If they are correct, what makes the book answers "better"? If they are not correct, what am I forgetting about or not understanding when it comes to putting the terms into order for my answer? Any help or clarification would be greatly appreciated!