how would I find each sum or difference of

Question

(5a-2b) + (-4a+5b)

what do I do with -2b when you line up the +5b?

Answer 1

The sum of the two terms in parentheses is a - 3b

If you want the difference, it should be written
(5a - 2b) - (-4a + 5b)
which is the same as
(5a - 2b) + (4a - 5b) = 9a - 7b