Answer: he bought 12 books.
Step-by-step explanation:
Let x represent the number of books that Greg bought.
Greg ordered some books online for $6 each. This means that x books would cost $6x
He paid a total of $3 for shipping. The total cost of the purchase was $75.00. This means that
6x + 3 = 75
Subtracting 3 from the left hand side and the right hand side of the equation, it becomes
6x + 3 - 3 = 75 - 3
6x = 72
Dividing the left hand side and the right hand side of the equation by 6, it becomes
6x/6 = 72/6
x = 12
