Question 22507
Try this:
Start with the slope-intercept form.
f(x) = mx+b Now write two equations using the given data.

f(6) = m(6)+b = -1
f(3) = m(3)+b = 8  Solve this system of equations by subtracting one from the other to find the slope, m.

6m + b = -1
-(3m + b = 8)
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3m = -9  Divide both sides by 3
m = -3

The slope is -3.