Re: Checking simplified algebraic expressions (the -3 test)

Ok, I have a better plan thanks to some of the suggestions I have
gotten here. I tell my students the following. If they have time at
the end of the test, plug in zero and seeif that answers match. If
they don't, then their answer is wrong and they must find the mistake.
If  the answers do match their answer may be right, but if they still
have time try out 1 or -1. If the answer do not match then they have a
mistake. If they do match then try out other numbers as time permits.
Using this plug in technique they can never be sure their answer is
right but they will probably catch a mistake if the answer is wrong.

Hey I just though of something is there a maximum number of potential
false matches given the order of the unsimplified and simplified
expression.