Answer:

Explanation:
Hi there!
What we need to know:
- Linear equations are typically organized in slope-intercept form:
where m is the slope and b is the y-intercept (the value of y when x is 0) - Perpendicular lines always have slopes that are negative reciprocals (ex. 3 and -1/3, 5/6 and -6/5, etc.)
1) Determine the slope (m)
y=x-9
Rewrite the equation
y=1x-9
Now, we can identify clearly that the slope of the line is 1. The negative reciprocal of 1 is -1, so therefore, the slope of a perpendicular line would be -1. Plug this into
:

2) Determine the y-intercept (b)

Plug in the given point (7,9) and solve for b

Add 7 to both sides to isolate b

Therefore, the y-intercept is 16. Plug this back into
:

I hope this helps!