Compare and contrast simplifying the numeric expression 3 – (2 + 5) to the algebraic expression 3x – (2x + 5)

The operations carried out on the numeric expression, such as distribution of the negative sign, addition and subtraction are the same as that for the algebraic expression. However, the presence of the variable x in the algebraic expression means we cannot combine all of the terms, only the like ones.
The numeric one simplifies to:
3 - (2 + 5) = 3 - 7 = -4
While the algebraic one simplifies to:
3x - (2x + 5) = 3x - 2x - 5 = x - 5