Answer:
First blank: 6a
Second blank: 2/3
Third blank: 21.6
Fourth blank: 3.9
Step-by-step explanation:
Basically, all you need to do is distribute the 2/3 to the stuff inside the parentheses. That means in the first blank, write 6a inside since you're multiplying 2/3 and 6a, and then in the second blank you write 2/3 since you're multiplying 2/3 and 9 together.
2/3*6a+2/3*9 = 21.6 is what you should have.
Now, just solve for a.
4a+6 = 21.6
4a=15.6
a=3.9
