Posted by lewis on Tuesday, March 17, 2009 at 1:26am.
which number cann be used in place of the variable in each rational expression
a^2b^2/ab

math  drwls, Tuesday, March 17, 2009 at 8:31am
What you have written equals a + b, because the numerator equals (a+b)(ab); so the ab term cancels the denominator.
Your question is unclear. Both a and b can be any number.