# Help Me Figure Out What R Is

find the value of R so that the line through (3, 13) and (R, -5) has a slope of 8

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You know that the formula for slope is given by: $$m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}}$$ and given that the value for $m=8$. Use this to find the value of $R$.
We have $$m = \frac{-5-13}{R-3} = 8$$ and solve for $R$.