1. The problem statement, all variables and given/known data My textbook never explains well so I have to figure out how to do problems by reverse engineering using the solution manual. However, here is one operation that I simply cannot reverse engineer. I do not see a common pattern in these four problems. I can't figure out what operation is going on here. In the first one it looks like they're just multiplying i by x and j by y which would work but given the other 3 examples, that's not what's happening. I understand all the other steps but this is one operation that I don't understand. here are the full problems in case you need to see more context.