Susan have 9 books.
Explanation:
Given that Marge has 4 more than 2 times as many books as Susan.
Let x represents the number of books that Susan has.
The relationship is written as
To find: Number of books that Susan have.
The number of books that Susan have can be determined by solving the expression for x.
Thus, we have,
Subtracting 4 from both sides of the equation, we get,
Dividing both sides by 2, we get,
Therefore, Susan has 9 books.