Elizabeth, heather, and erin share the same birthday. they’ve decided to join together to have one big birthday party. the event location says it will cost $70 for the rental of the space and $15 per guest. each girl invites x number of guests, including themselves in their guest count.
the girls have each written a different correct expression to represent the total cost of the party. explain how each of the 3 expressions below represents the total cost.
(a) elizabeth’s expression: 15x + 15x + 15x + 70
(b) heather’s expression: 15(x + x + x) + 70
(c) erin’s expression: x(15 + 15 + 15) + 70