M(9, 8) is the midpoint of mc136-1.jpg. The coordinates of S are (10, 10). What are the coordinates of R?

Question

campbell_st · Answer

well the midpoint formula for x is 

$$x_{m} = \frac{x_{s} + x_{r}}{2}$$

so substitute $$x_{m} = 9...and... x_{s} = 10$$

so you get 

$$9 = \frac{10 + x_{r}}{2}$$

so to find xr   multiply both sides of the equation by 2 and then subtract 10


for y, the  formula is 

$$y_{m} = \frac{x_{s}+x_{r}}{2}$$

and y_m = 8 and y_s = 10

solve for y_r

hope this helps