Find the slope that contains the points (-4,3) and (4,9)

Let A and B have (-4,3) and (4.9) as coordinates, respectively, and a the slope.
To find the slope using the known coordinates of two points, we apply the formula:
a = Δy / Δx
Δy represents the subtraction of the y-coordinates of the points and Δx the subtraction of the x-coordinates.
So Δy = yB - yA
     Δx = xB - xA

So a = Δy / Δx
a= (yB - yA) / (xB - xA)
a = (9 - 3) / (4 + 4)
a = 6/8

So the slope of the line that contains the points (-4,3) and (4,9) is a = 6/8

Here's a picture representing the line with the 2 points.

Hope this helps! :)