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# coordinates

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A line segment has one endpoint at (6, 8) and midpoint at (-1, -1). What is the sum of the coordinates of the other endpoint?

Jul 18, 2021

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The formula of a midpoint of two points is just the average of the x, the average of the y.

$$(\frac{(6+x)}{2},\frac{(8+y)}{2}) = (-1, -1) \\ 6+x = -2 \\ 8+y = -2 \\ x = -8 \\ y = -10$$

-8 + -10 = -18

Jul 18, 2021