What is the simplified form of the expression 3a + 7 - a - 7

You can simplify expressions by simplifying parentheses by using the distributive property and combing like terms.

Combining like terms is the process of adding up numbers with the same variable(s) and exponent. If a term does not have an exponent then an exponent of 1 is implied.

There is no parentheses in the expression 3a + 7 - a - 7 
But, there are like terms in the expression.

Which are the like terms?

3a and a are both like terms. They both have the same variables and they both have the same exponent.

7 and -7 are like terms, too.

3a + 7 - a - 7
2a

So, 2a is the simplified version.

Hi so -7 and +7 cancel out to be 0. 3a-a is 2a. So it's 2a+0. You don't need the +0 so it's just 2a