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. (20 points) a
y = 8x

b
y = one-eighth x

c
y = 9x

d
y = one-ninth x

C  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

step-by-step explanation:

abc