Answer:
1. X > 1
Explanation:
We know
because
. That's why
.
We can now subtract 1 in both sides of the inequality:
.
Factoring
as a difference of cubes, we get:
.
Thus, we have two factors whose multiplication is positive. Then, both are positive or both are negative. The second case is impossible, because
can never be positive. The reason is the following:

witch is always positive because
is a sum of squares, and the squares are always positive.
We conclude that both
and
have to be positive, and then
implies
