Answer:
-14x + 34y
Step-by-step explanation:
First, find the sum of the two expressions by adding like terms:
(15x + 15y) + (-18x + 15y)
= -3x + 30y
Now, subtract 11x - 4y, again by combining like terms:
(-3x + 30y) - (11x - 4y)
= -14x + 34y
So, the answer is -14x + 34y
