Answer:
![y=9x](https://img.qammunity.org/2021/formulas/mathematics/high-school/p0lp03axvltfpy3s4uinpqvaydpa6unqiu.png)
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
![y=kx](https://img.qammunity.org/2021/formulas/mathematics/middle-school/15ggalazf8cpjag5fv34y8ftpnv14l6oxo.png)
In this problem we have
y=18 when x=2
Find the value of the constant of proportionality k
---->
![k=(18)/(2)=9](https://img.qammunity.org/2021/formulas/mathematics/high-school/okjyb2bfbmj89jsgt82ksc8apoh6su2srt.png)
therefore
The equation is equal to
![y=9x](https://img.qammunity.org/2021/formulas/mathematics/high-school/p0lp03axvltfpy3s4uinpqvaydpa6unqiu.png)