Question 272649
your point pairs are:


(x1,y1) = (-9,-9)


(x2,y2) = (7,-9)


the slope is the change in the value of y divided by the change in the value of x.


the change in the value of y is y2 - y1 = (-9) - (-9) = (-9) + 9 = 0.


the change in the value of x is x2 - x1 = (7) - (-9) = (7) + (9) = 16


your slope is 0/16 = 0


I believe you have the right answer.


the slope intercept form of the equation of a straight line is:


y = mx + b


where m is the slope and b is the y intercept.


since the slope is 0, we can use either one of the 2 points to find the equation.


let's use the point (x1,y1) = (-9,-9)


since the slope is equal to 0, your equation becomes:


y = 0x + b


we let y = -9 and x = -9 to get:


-9 = 0*(-9) + b


this becomes:


-9 = b


since b is the y intercept, your equation becomes:


y = 0x - 9 which is the same as:


y = -9


graph of your equation looks like this:


{{{graph (600,600,-10,10,-10,10,-9)}}}


what you have is a horizontal line at y = -9


if this is the equation of your line, then both points must be on that line.


your first point is (x1,y1) = (-9,-9).


look on the graph and you can see that when x = -9, y = -9.


your second point is (x2,y2) = (7,-9)


look on the graph and you can see that when x = 7, y = -9


in fact, x can be any value and y will be equal to -9.


you had it right.