Simplify the expression b - 7 + b - 8

I want to check my answer, I believe that it is 2b - 7 - 8 or 2b + (-1)

2b - 15

Step-by-step explanation:

b - 7 + b - 8

You combined the two b's correctly, but didn't combine the two constants, - 7 and - 8.

Those combine to - 7 + (-8) = - 7 - 8 = - 15, so the final answer is

2b - 15

you have - 7 and are subtracting 8 more, so you are moving 8 units left on the number line, so it has to get more negative.