Why does the elimination method work? Three students posed this today in our Video Summarizer Google Spreadsheet, and I believe this is a wonderful example of technology allowing for all voices in class to be heard.
I'll post a follow up after tomorrow's class with the answer. Great questions everyone. Keep them coming!
p.s. I assume everyone can solve this and graph it. Also, tell your parents about the invisible 1.
p.p.s. This works since 2x+y actually equals 8. So adding 2x+y to the LHS (left hand side) is the same as adding 8 to the RHS. The equality still holds. 3x=18. x=6. -PMM 9/25/2012