Question

The equation y = 0.75x + 10 describes the cost, y, of placing an ad with x words in the classified section of a newspaper. How many words are in an ad that costs $25?

Answer 1

y = cost = $25

25 = 0.75 +10

 subtract 10 from each side

15=0.75x

x = 15/0.75 = 20

 there were 20 words in the ad