Greetings from Brasil...
We can solve this question quickly building the graph and verifying the given points - refer to attached
If the half of the line has the point Y = - 2, then in the whole line we will have the point Y = - 4. For X the same: Half of the line has 6 units (from -3 to 3 in module), so the whole line will have 12 units - refer to attached
After these observations we can conclude that
B(9; -4)
y-coordinate = - 4
Note that
d(A; M) = d(M; B) = 2√10
and
d(A; B) = 4√10
............................................................................
There are other ways to resolve. We can use similarity of triangles OR the equation d(A; B) and d(M; B) which will result in an equation system with 2 variables
