Step-by-step explanation:

1. Write an expression that represents the length of the south side of the field

Solution:

L = (5x - 2) + (x² - 9) + (x² - 7x - 12)

2. Simplify the polynomial expression that represents the south side of the field

Solution:

L = (5x - 2) + (x² - 9) + (x² - 7x - 12)

L = x² + x² + 5x - 7x - 2 - 9 -12

L = 2x² - 2x - 23

3. Write the polynomial expression that represent the perimeter of the squash field and simplify

Solution:

Perimeter of squash field

P = 4x + 4x + x + x

P = 10x

4. Write a polynomial expression that represent the perimeter of pumpkin field

Solution:

Perimeter of pumpkin field

P = (5x - 2) + (5x + 2)

5. Simplify polynomial expression that represent the perimeter of the pumpkin field

Solution:

P = (5x - 2) + (5x + 2)

P = 10x