Answer:
We can use the vector addition property to find the coordinates of the points M, N, and I.
Let

To find M, we use the fact that MA + MB = 0. Therefore, we have:
MA = -MB
A - M = -(B - M)
A - M = -B + M
2M = A + B
M =

So, the coordinates of point M are

To find N, we use the fact that 3NA + NC = 0. Therefore, we have:
3NA = -NC
3A - N = -(C - N)
3A - N = -C + N
4N = 3A + C
N =

So, the coordinates of point N are

To find I, we use the fact that IM + 2IN = 0. Therefore, we have:
IM = -2IN
M - I = -2(N - I)
M - I = -2N + 2I
3I = M + 2N
I =

Substituting the values of M and N that we found earlier, we get:
I = (A + B + 2(3A + C)/4)/3
Simplifying this expression, we get:
I =

So, the coordinates of a point I are
