Question

How do I determine the points E and M

Answer 1

Relabel the spot that you have as M. (The reason we are keeping this coordinate is because it is correct just labeled wrong. It lines up perfectly with G and O both)

G is in the wrong spot, you have it in (2,2) it needs to go down 4 places to the coordinates (2, -2)

E will be located directly under O and directly across from G. So, it will be at the coordinates (-4, -2)