What is the slope of a line that passes through the points (-5,-3) and (9,-6)

To find the slope given two points, you need to subtract the two y values over the two x values
(-5,-3)  (9,-6)
-5 will be x1, and -3 will be y1. 9 will be x2, and -6 will be y2. You then need to put the numbers in the correct place in the equation.
y2-y1      -6-(-3)     -9
=   =  
x2-x1       9-(-5)     14
Now that we have the slope (-9/14) you can use one of the coordinates to find the value of b.
Let's use (9,-6).
-6=-9/14(9)+b
-6=-81/14+b
+81/14
b=-3/14
Your final equation is y=-9/15x-3/14

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