SOLUTION: The coordinates of M, the midpoint of AB, is (-1,2). If the coordinates of A are (3,-6), find the coordinates of point B.

Algebra ->  Length-and-distance -> SOLUTION: The coordinates of M, the midpoint of AB, is (-1,2). If the coordinates of A are (3,-6), find the coordinates of point B.       Log On


   



Question 265605: The coordinates of M, the midpoint of AB, is (-1,2). If the coordinates of A are (3,-6), find the coordinates of point B.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The formulas for finding the x and y
coordinates of the midpoint of a line is:
M%5Bx%5D+=+%28x%5B1%5D+%2B+x%5B2%5D%29%2F2
M%5By%5D+=+%28y%5B1%5D+%2B+y%5B2%5D%29%2F2
given:
M%5Bx%5D+=+-1
M%5By%5D+=+2
x%5B1%5D+=+3
y%5B1%5D+=+-6
-----------------
M%5Bx%5D+=+%28x%5B1%5D+%2B+x%5B2%5D%29%2F2
-1+=+%283+%2B+x%5B2%5D%29%2F2
-2+=+3+%2B+x%5B2%5D
x%5B2%5D+=+-5
and
M%5By%5D+=+%28y%5B1%5D+%2B+y%5B2%5D%29%2F2
2+=+%28-6+%2B+y%5B2%5D%29%2F2
4+=+-6+%2B+y%5B2%5D
y%5B2%5D+=+10
The coordinates of point B are
B(-5,10)