Each flower costs $1.25 and the delivery charge $15. Roger want to spend $80 on flowers. Let x be the number of flowers roger buy.
We can now build up the equation:
80 = 1.25x + 15. We need to solve for x.
Let's subtract 15 from both sides
80 - 15 = 1.25x + 15 - 15
65 = 1.25x
Divide both sides by 1.25 to have x on side and its value on the other
65/1.25 = (1.25x)/1.25
52 = x
So Roger can buy 52 flowers.
Let's check our answer:
1.25x + 15 = 1.25 * 52 + 15 = 65 + 15 = 80.
Our answer has been approved.
Hope this helps! :D