David C. answered 01/29/21
Enthusiastic, patient, and effective tutor.
The slope you calculated is correct.
The error is with the constant term.
Recall that in the slope intercept form of the line
y = mx + b
the 'b' term is the y-intercept.
The problem told you that the y-intercept is 18 and so,
the correct equation is:
y = 9/10x + 18
Good work on finding the slope correctly.