your friend bought 3 bags of wild bird seed and an $18 bird feeder. each bag of birdseed costs the same amount. if your friend spent $45, find the cost of one bag of birdseed. a. 3 18x = 45; $2.33 c. 3 x 18 = 45; $24 b. 3x 18 = 45; $9 d. 3x - 18 = 45 ; $21