Find the value of r so that the line that passes through (r,-5) and (3, 13) has a slope of 8.

I thought it was -18/5, but now I'm rethinking it because if the slope is 8 then what is r ?
Am I correct, or am I wrong?

Question

Find the value of r so that the line that passes through (r,-5) and (3, 13) has a slope of 8.

I thought it was -18/5, but now I'm rethinking it because if the slope is 8 then what is r ?
Am I correct, or am I wrong?

baru · Answer

how did you get -18/5
what formula do you have for finding slope?

atsie · Answer

I have $$M = y2 - y1 / x2 - x1 $$
as the formula for finding slope. 
Maybe it'd look better, if I put it like this.
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