Question

The midpoint of AB is M(0,−3). If the coordinates of A are (2,−5), what are the coordinates of B?

Answer 1

Answer:  (-2,-1)

Step-by-step explanation:

A and B are the endpoints and  we know that to find the midpoint, we need to find the average between the x and y  values.

The x coordinate of A plus the x coordinate of B has to equal 0.  We can represent that by the equation

$\frac{x+2}{2} = 0$     now solve for x to find the x coordinate of B by first multiplying both sides by 2.

x + 2 = 0    Subtract 2 from both sides

   -2    -2

x =  -2  

So the x coordinate is -2  now find the y coordinate using the same method.

$\frac{-5+y}{2} = -3$     Multiply  both sides by 2

-5 +y = -6    Add -5 to both sides

+5          +5

y = -1  

The y coordinate is -1

so the coordinates of B is (-2,-1)