To find this answer, we need to multiply 3.57 by 12.

Therefore, 12 planks will cost $42.84.
Answer:
2 
Step-by-step explanation:
First, we will turn 5 2/5 into an improper fraction:
5 * 5 = 25 + 2 = 27/5
So they worked for 27/5 days.
We want to divide the days worked by the distance to get the unit rate of distance per day:

So our answer is 2 
Hope this helps, have a great day! :D
Answer:
-45 is xn
The x=3 and x=-15 multiply them together which is the answer to xn