7/9 of his trees are oak trees
First attachment = 3
Second attachment = -7
Third attachment = 25
So :

?
First, you want to bring everything together on the top of the fraction.
12=24/2 so you can have

Add like terms -- 12 +24 = 36

Now we are at

Which is the lowest possible simplified version while remaining at exact value.
Feel free to check my math! I kinda did this off the top of my head.
Answer:
5x + 30
Step-by-step explanation:
5(5+x)
=(5)(6) + (5)(x)
=30 + 5x or 5x + 30