е)
k^2/(k+4)^2 - 16/(-4-k)^2 = k^2/(k+4)^2 - 16/(-k-4)^2 = k^2/(k+4)^2 - 16/(k+4)^2 = (k^2 - 16)/(k+4)^2 = (k+4)(k-4)/(k+4)^2 = (k-4)/(k+4)
ж)
9m^2/(m-n)^2 - 9n^2/(n-m)^2 = 9m^2/(m-n)^2 + 9n^2/(m-n)^2 = 9m^2 + 9n^2/(m-n)^2 = 9(m^2 + n^2)/(m-n)^2
е)
k^2/(k+4)^2 - 16/(-4-k)^2 = k^2/(k+4)^2 - 16/(-k-4)^2 = k^2/(k+4)^2 - 16/(k+4)^2 = (k^2 - 16)/(k+4)^2 = (k+4)(k-4)/(k+4)^2 = (k-4)/(k+4)
ж)
9m^2/(m-n)^2 - 9n^2/(n-m)^2 = 9m^2/(m-n)^2 + 9n^2/(m-n)^2 = 9m^2 + 9n^2/(m-n)^2 = 9(m^2 + n^2)/(m-n)^2