When you simplify, you are just taking the equation down to it's simplest form, not solving it. Evaluation involves actually solving the problem.
Expression has no answer. a equation has an answer
it has to have an x number in it.
A variable expression includes variables.
The difference is that an algebraic expression has numbers, symbols and variables, but a verbal expression has only words.
Evaluating the expression.
It is "evaluating".
Evaluating the expression
That is sometimes known as EVALUATING the expression.
Simplifying an expression is getting rid of any brackets or parentheses, performing as many operations as you can - including combining like terms. To evaluate an expression you would substitute the numerical values of all the variables, carry out all the operations (addition, multiplication etc) in the expression to reach the answer - the numerical value of the expression.