If the m-th power of the second power B of negative two thirds A is the same as the n-th power B of 4A, then M-N=

If the m-th power of the second power B of negative two thirds A is the same as the n-th power B of 4A, then M-N=

According to the meaning of the title
n=2
m=1
m-n=1-2=-1