To find the equation of a line given a point it passes through and its slope, you can use the point-slope form of a linear equation:
y - y1 = m(x - x1)
Where (x1, y1) is the given point, and m is the slope.
Using the given point (-4, 9) and the slope -1, the equation becomes:
y - 9 = -1(x - (-4))
y - 9 = -1(x + 4)
Now you can simplify the equation by distributing the -1:
y - 9 = -x - 4
Finally, simplify it further by adding 9 to both sides:
y = -x + 5
So, the equation of the line is y = -x + 5.