Answer:
120poles
Step-by-step explanation:
Given
Length of each poles of the paddock = 30
Since a square has 4 sides, the perimeter of the square shaped paddock is what we are to look for.
Perimeter of a square = 4L
L is the length of each side of the paddock
Perimeter = 4(30)
Perimeter of the square = 120
Hence he used 120poles for the paddock
Recall the definition of the composition between two functions:

Similarly, but not always the same:

Use the rules of correspondence of the functions f and g to find the compositions:

Then:

On the other hand:

Therefore, the answers are:
2-3 is -1. difference between two rational numbers that make a negative