(-3m2n3)2 (-2m3n) 3(1/72m2n3)
Use PP -3m2n3 must be multiplied 2 times and -2m3n must be multiplied 3 times, but 1/72m2n3 does need to (Because there is no exponent, and that is same as that there is 1).
It can be multiplied with same bases.
And it can be divided
We can get the results that a is -1, b is 11, and c is 6, so -1+11+6 is equal to 16