Newbie questions

What is the difference between and Expression and Expression.Symbolic?

I’m trying to dynamically write LaTex in C# using Math.NET Symbolic. For example:
Given a,b,c are int and
Expr f = (a * x * x + b * x + c );
Can I evaluate f at x+h and take the limit as h goes to 0 in a step by step fashion and output the LaTex on each step?

I’m quite familiar with C#, LaTex and math in general, but I’m running into difficulties with implementation of Math.NET symbolics .