Question

How do I prove that when two points are connected create a positive or negative slope?
I have to prove points: (2,5)(12,19) make a positive line.
And then points (21,5)(12,19) create a negative line.
But im not sure how to prove it.

Answer 1

Do you know the slope formula?

Answer 2

is it the m= y2-y1/x2-x1?

Answer 3

yes. Just use that on each pair of points to show that one slope is positive and the other negative.

Answer 4

okay one second

Answer 5

okay, for the positive slope points I got 7/5 when I plugged the points into the formula

Answer 6

Me too. Go for the next one.

Answer 7

okay i got 14/-9

Answer 8

me too.Good job.