Question

Point m (3, -2) is the midpoint of ab if the coordinates of a are (-1, 4) then find the coordinates of point b

a.( 0,0)
b. (1,1)
c. (7,-8)
d. (2,2)

Answer 1

B(7,-8)

Explanation:

Coordinates of m (3,-2)

Coordinates of A (-1,4)

We need to find the coordinates of point B if m is the midpoint of AB. Let the midpoints be (x,y).

Mid-point formula is :

`(x,y)=((x_1+x_2)/(2),(y_1+y_2)/(2))`

So,

`(3,-2)=((-1+x)/(2),(4+y)/(2))\\\\\text{It means,}\\\\(x-1)/(2)=3\ \text{and}\ (4+y)/(2)=-2\\\\x-1=6\ \text{and}\ 4+y=-4\\\\x=7\ \text{and}\ y=-8`

So, the coordinates of B is (7,-8).