M(0,4) is the midpoint between R(x,y) and S(7,9). Find the coordinates of R.

Question

Need to find coordinate. Enter answer as an ordered pair, including the comma.

Answer 1

Given points say R(x1,y1) = (x,y)

S (x2,y2) = (7,9)

Mid point of RS is M = (x1+x2/2,  y1+y2/2)

(0,4) = [(x+7)/2,(y+9)/2]

(x+7)/2 = 0                      and          (y+9)/2 = 4

Multiple to each sde by 2.  and     Multiple to each sde by 2.

x+7 = 0                            and        y+9 = 8

Subtract 7 from each side.  and     Subtract 9 from each side.

x+7-7 = 0-7                      and             y +9-9 = 8-9

x = -7                               and                   y = -1

R(x,y) = (-7,-1)