Dominic is a landscape architect and is designing a garden with an area of up to 500 square feet. He will use two types of plants: zinnias and petunias. Each zinnia plant requires 1.6 square feet of ground and each petunia plant requires 1.8 square feet of ground. Each zinnia plant costs $4 and each petunia plant costs $3, and the architect must spend no more than $600. Let z represent the number of zinnia plants and p represent the number of petunia plants.

Three of the constraints for this situation are z≥0, p≥0, and 1.6z+1.8p≤500.

What is the other constraint for this situation?
Enter your answer in the boxes.

z + __
p≤ __

Marshall uses the polynomial identity (x−y)2=x2−2xy+y2 to show that 8² = 64.

What values can Marshall use for x and y?

x = 8 and y = 64

x = 10 and y = 2

x = 2 and y = 6

x = 64 and y = 0