Because the solution of m is: x>3 or X.

And m = n = R.

So the solution of n belongs to-1

Because m ∩ n = (3 3,4)

So the solution of n is:-1

That is, two solutions to the inequality of n are: x 1=- 1, x2=4.

So: a=-3, b=-4.

D: a+b=3

Second question, is there a problem with your question? What is the real number k? There is no real number k in your inequality!