D is the midpoint of line CE. E has coordinates (-3,5), and D has coordinates (2 1/2,1). Find the coordinates of C.

Question

D is the midpoint of  line CE. E has coordinates (-3,5), and D has coordinates (2 1/2,1). Find the coordinates of C.

anonymous · Answer

C is (8,-3)

anonymous · Answer

let C to be (x,y) then solve for x in [ x+(-3)]/2=2 1/2  , and solve for y in (y+5)/2 =2

anonymous · Answer

$$(\frac{x_C+x_E}{2},\frac{y_C+y_E}{2}) = (x_D+y_D)$$
$$E = (-3,5) = (x_E, y_E)$$$$D=(2\frac{1}{2},1) = (x_D,y_D)$$
$$(\frac{x_C+(-3)}{2},\frac{y_C+5}{2}) = (2\frac{1}{2}+1)$$

$$\frac{x_C-3}{2}=2\frac{1}{2}=\frac{5}{2}$$$$\frac{y_c+5}{2}=1$$

$$x_C-3=5 => x_C=8$$$$y_C+5=2 => y_C=-3$$