Proof Writing · Hard problem

Assume $x^2 \le 9$ and show $x^2 > 9$.

Assume $x^2 > 9$ and show $x > 3$.

Assume $x \le 3$ and $x^2 > 9$, and derive a contradiction.

Assume $x > 3$ and $x^2 \le 9$, and derive a contradiction.