ok this isn't as bad as it looks. all you have to do is multiply the terms in the parentheses by the terms outside of them. so it would b 9 x (r-s) + 5 x (2r -2s).
You would then get (9r-9s) + (10r-10s). Remove the parentheses and combine like terms. 9r + 10r is 19r and -9s plus -10s is -19s. so the answer is 19r - 19s.
