Combine like terms.

6b plus 7b-10=
Would I add 6b + 7b=13b-10
13b-10=3b?

Would this be correct? Please advise.

No.

You can't combine a term with an unknown with a term without an unknown.

6b plus 7b-10= 13b - 10

So would it just be 13b-10?

Yep.

Let's suppose that b = 3. 13b = 39
13b - 10 = 29

What would the answer be if b = 2?

I am sorry Ms. Sue I do not understand this.

You already posted the answer. What don't you understand?

b is an unknown number

To combine like terms, you need to add or subtract coefficients of the terms that have the same variable. In this case, you have 6b and 7b, which are both terms with the variable "b".

Start by adding the coefficients of the like terms: 6b + 7b = (6 + 7)b = 13b.

The rest of the expression remains the same: -10.

So the simplified expression is 13b - 10.

Your initial attempt, where you wrote 13b - 10 = 3b, is not correct. The result is 13b - 10, not 3b.