Mark bought gifts for his friends, and each gift cost $9. let y represent the total cost and x represent the number of gifts. write an equation to represent the proportional relationship between the total cost and the number of gifts he bought.
y = 8x
y = one-eighth x
y = 9x
y = one-ninthx

9x

Step-by-step explanation:

Cost of one gift is $9

cost of x gifts = 9 * x = 9x

Hence

y=9x is the required equation of our function where

y represent the total cost incurred and x is the number of gifts. To evaluate total cost we have to multiply the number of gifts with 9 .

For example if there are 7 gift bought, the total cost will be

y=9(7)

= 63

cost of 7 gifts is $63

y -5 = (-1/4)(x + 8)

step-by-step explanation: