=a^4

(-m 5) divided by (-m) 2

=-m^3

(ab)^4 divided by (ab)^2

=(ab)^2

X n+3 divided by x n+ 1

=x^2

(-x) n+3 divided by (-x) n+ 1

=x^2

(y 3) 4 divided by (y 3 times y 2) 2 = y 2.