Answer:
Step-by-step explanation:
heres what you you do
1. do the stuff in the parantathes (nothing)
2. break parenthates ( now it should look like this 7a-b*7a+b)
3. add the same thing together (7a's cancel each other out)
4. now your left with (-b+b now they cancel each other out)
hope this helps, have a good day!
