Answer:
3 + 3x + 15y
Step-by-step explanation:
You may find it easier to write these two expressions into column form:
(-4+5y-2x)
+ (5x+7+10y)
Combine like terms (do this for constants, x and y terms):
(-4+5y-2x)
+ (5x+7+10y)
-------------------
3 + 3x + 15y
