# Question: substitution without evaluation

February 18 2013 by
false

1

Create an expression like g:=(3x^2 - 3y^2)/(x-y).

I would like the substitution x= 5, y=2 to produce the unsimplified, unevaluated expression (3*5^2-3*2^2)/(5-2).

I've tried various combinations of subs and subsop to no avail. Some piece of the expression is always evaluated.

Any suggestions?