Question

Frank ordered some books online for $5 each. he paid a total of $4 for shipping. the total cost of the purchase was $89. how many books did he buy? (please answer both A and B)​

Answer 1

To find A.), we must create a linear equation. Let b be the number of books Sam ordered. We write 5b because each book is 5 dollars. Then we add 4 dollars to the equation to represent the shipping fee. Then we write "equals to 89", because it says that is the total cost. So we get the equation
`5b+\$4=\bold{\$89}`

To find B.), we must solve the equation. Isolate the variable, by subtracting 4 from both sides. We then get
`5b=\$85`. Now we divide by 5 to get only the variable and to get rid of the coefficient. We get
`b=17`. So Sam bought 17 books.