The equation has to (or be transformed to) contain one object in the left side and the other object at the right side multiplied by a constant, without an independent term.
Hmm they're both even numbers so maybe we can start by cutting each number in half.

18 and 48 had 2 as a common factor.
So factoring a 2 out of each number was the same as cutting each number in half. Try to do something similar with the 9 and 24. They each have something in common.
First you can take out a 3. And an x and a y. Thus, 3xy(3x+4y) is the answer.