Answer:
7x+12y
Step-by-step explanation:
Simplify
4x+9y+3(x+y)
Use the distributive property to multiply 3 by x+y.
4x+9y+3x+3y
Combine 4x and 3x to get 7x.
7x+9y+3y
Combine 9y and 3y to get 12y.