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 the line crosses the y-axis) - 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)

This equation can be written as
. Now, we can identify clearly that -1 is the slope of this line. Because perpendicular lines have slopes that are negative reciprocals, we know that the slope of the line we're calculating for is
, or just 1.
Plug 1 into
as the slope:

2) Determine the y-intercept (b)
Recall that the y-intercept is the value of y when the line crosses the y-axis. It occurs when x is equal to zero.
The given point is (0,9), meaning that y is 9 when x is 0. Therefore, the y-intercept is 9. Plug this into
:

I hope this helps!