I need help with number 3

x-y -9 = 0
Solve for y:
Subtract X from each side:
-y-9 = -x
Add 9 to each side:
-y = -x +9
Multiply everything by -1:
y = x-9
Now you have Y, use slope intercept form to solve for the slope and Y-intercept.
Slope intercept form is y = mx+b
m = slope, and b = Y- intercept.
y = x-9
There is only 1x so slope = 1, b = -9, so y-intercept = -9
The y-intercept is when X is 0, so the first point on the graph would be (0,-9)
Use the equation y = x-9 to find more points:
replace X with whole numbers and solve for Y:
x=2: y = 2-9, y = -7 for point (2,-7)
Now you have 2 points to make your graph.