Answer:
2x-5 if u want u can substitute any other variables and constant
1st gift shop:
120/4 = 30 cents each
180/6 = 30 cents each
390/13 = 30 cents each
2nd gift shop:
204/7 = 29.14 cents each
192/8 = 24 cents each
270 /9 = 30 cents each
360/10 = 36 cents each
so if both gift shops have a fixed price then the 9 post cards would be the answer since it matches 30 each like the 1st gift store
7x= 28 so x is 4 and y is 1.. So (4,1)
I think your answer would be A?