Is it possible to create a function to shorten a variable?

Hello.

I would like to know it is possible to create a function ("b" in the example below) in order to shorten the expression of another variable. For example:

a = 2;

b = 0.5*c + 1;

c = b + a;

Solving the system of equations above manually, a value of c = 6 and b = 4 is achieved. That being said, is there a command that lets me reproduce this manual calculation, or do I have to obligatorily replace "c = b + a" with "c = 2*(a+1)" in order to solve this system? Thanks in advance!

[Cam Salzberger]

Are you trying to solve this system of equations symbolically or numerically? If symbolically, do you have the Symbolic Math Toolbox (check ver output).