n=2

2. The original formula = (-1) 2n+1=-1.

3. Original formula = (4 * 5) 2 = 400

There are several situations: m and n.

One is 3, and the other is 4 or.

One equals 4 and the other equals 3.

Or one is 5 and the other is 2.

Or one is 6 and the other is 1.

Or a 7 and a 0.