No offense GrinS, but how the hell did you come up with the answers? I feel like I'm looking at Stephen Hawking's work because I can't understand any of that three pages of work. lol. It took me literally 13 notebook lines to come up with it, but whatever floats your boat as long as you get it. Props to us.

But yeah, your teacher will be looking for actual equations and you defining your variables, and showing how you used substitutions. for exactly, when I say Plug #4 into #2 to get a=77, I mean:

a-53+a=101

2a=101+53

2a=154

a=77

etc....