The deli charges $7.50 for a salad weiging 3 pounds. a salad weighing 4 pounds costs $9. what equation can be used to represent the cost for the salad y for x pounds of salad?

3x - 7.5y = 0  

4x - 9y = 0

Step-by-step explanation:

Let x denotes the the weight of the salad in pounds

Let y denote the cost of the salad.

Then, Cost of 3 pounds of salad = $7.5

We get the equation, 3x = 7.5y

3x - 7.5y = 0   (1)                      

Cost of 4 pounds of salad = $9

4x = 9y

4x - 9y = 0 (2)

(1) and (2) are the equation representing cost of salad y for x pounds.