It is known that the sum of the monomial 7amb2 and - 13a4bn-1 is a monomial, then M=______ ,n=______ .

It is known that the sum of the monomial 7amb2 and - 13a4bn-1 is a monomial, then M=______ ,n=______ .

From the sum of the monomial 7amb2 and - 13a4bn-1 is a monomial, M = 4N − 1 = 2, M = 4N = 3