The answer is (3x + 5) ^2
Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form
or 
In this problem we have
y=18 when x=2
Find the value of the constant of proportionality k
----> 
therefore
The equation is equal to

X^2 +3x - 18 is the answer