Max placed the same number of books on 4 shelves and he placed 7 books on the last shelf. There are a total of 27 books on all the shelves. Find the number of books Max placed on the first shelf.

Which statement correctly describes how to solve the problem algebraically?

a) Solve the equation 4x−7=27 where x is the number of books Max placed on the first shelf.

b) Solve the equation 4x+7=27 where x is the number of books Max placed on the first shelf.

c) Subtract 7 from 27 and then subtract 4.

d) Subtract 7 from 27 and then add 4.