Positive 38. This is a subtraction problem. You just need to find the difference between the two numbers.
I think the first one is correct. Since “three less than z squared” insinuate that the value is 3 units less than the value z^2
(X+3)(y-2)
F(x-3)-2
This cheat sheet may help
Let's Just See How Many Times 30 Goes Into 180

Since 8 trash bags last 30 days, let's multiply

ANSWER
You'll Need 48 Trash Bags For 180 Days