Question: How to substitute a variable into an expression contained within a parenthesis in Maple?

The following differential equation occurs during blending of two fluid in a continuous flow stirred tank

I want to replace the quantities in parenthesis on the RHS with the following variables (so-called deviation variables) where the overbar variables are constants and x1, x2 and x are variables.

When I use the subs command or algsubs command, it doesn't perform the substitution.

What is the best way to perform this operation?

Please Wait...