Answer:
We conclude the equation is linear because it can be rewritten in the form 
 .
.
Hence, option D is correct.
Explanation:
The slope-intercept form of the line or linear equation 
 
 
where
  is the slope is the slope
  is the y-intercept is the y-intercept
 
Important Tip:
The graph of a linear equation is always a straight line. 
Convert the given equation in the slope-intercept form

subtract 18x from both sides

simplify

divide both sides by 9

Now, comparing the equation 
 with a slop-intercept form of linear equation
 with a slop-intercept form of linear equation
- The y-intercept b = -416/9
Therefore, we conclude the equation is linear because it can be rewritten in the form 
 .
.
From the attached graph, is also clear that the graph of the equation 
 is a straight line.
 is a straight line.
Hence, option D is correct.