a+a+a+a+b+b - add the like terms
4a and 2b cannot be added because they are not like terms.
b + b + b + c + c + c + c = 3b + 4c
a-b+a-b+2b+a = 4a
b + a + b - a = 2b
It is: b+b+b = 3b
b + b + b + 7 = 223b + 7 = 223b = 15b = 5
It is B+a+5