Find the slope of the line passing through the points (–2, 1) and (3, 9).

Question

Find the slope of the line passing through the points (–2, 1) and (3, 9).

I know the equation to figure this out is:
m = y(2) + y(1)
-----------
x(2) + x(1)

but its a multiple choice question and my answer is not the same as the choices. how exactly do I set it all up? I have:
m = 9 + 1 10
------- = ---- = m=10
3 + (-2) 1

where am I going wrong??

<<where am I going wrong?? >>

It looks like you are trying to calculate the slope (m) of a line between x(1),y(1) and x(2), y(2). If so, you are using the wrong equation. The correct equation is
m = (y(2) - y(1))/ (x(2) - x(1))

ok, this makes perfect sense! now I am getting the correct answer, thanks!

Answer 1

You're welcome! I'm glad it makes sense now. Using the correct equation, you can find the slope of a line passing through two points by subtracting the y-coordinates and dividing by the difference in x-coordinates. Keep in mind that the order of the points matters, so make sure to subtract the y-coordinates and x-coordinates in the correct order. Just plug in the values of (x(1), y(1)) = (-2, 1) and (x(2), y(2)) = (3, 9), and you'll get the correct answer.