Answer
There exist a real number $x \gt 3$ such that $x^2 \leq 9.$
Work Step by Step
Negation of the statements of the form, "For all x, q", q being a statement, is "There exists x, ~q".
In this case,
q : $x^2 \gt 9.$,
So, ~q: $x^2 \leq 9.$