Answer:
The coordinates of B is (-8,-5).
Step-by-step explanation:
The midpoint of line AB is M. The coordinate of M is (-6,-4).
The coordinates of A is (-4,-3)
We need to find the mid point of B.
If M(x,y) is the midpoint of the coordinates (x₁,y₁) and (x₂,y₂). The mid point theorem is used as follows :

Let the mid point of B is (x₂,y₂). Put (x,y) = (-6,-4), (x₁,y₁) = (-4,-3).

So, the coordinates of B is (-8,-5).