x(3) < 200
Step-by-step explanation:
If Frank were to triple...
Frank's number of books is unknown.
Unknown = X, because we don't know.
If you put a number next to a number inside parenthesis (), it means it's multiplying
x(3) = Frank is Tripling his books
< 200 = Frank still has less than Emily's book collection.
x(3) < 200 = If Frank tripled his books, he'd still have less than Emily.