Answer:
You need to make the denominators the same.
Step-by-step explanation:
-2/3 + 3/5 has a common denominator of 15 if you multiply the denominators together, but you must multiply the upper half too.
-2/3 + 3/5 =
-10/15 + 9/15
(= 9/15 - 10/15)
= -1/15
