3)
If y=f(x), then
[tex]\begin{gathered} y=f(x) \\ \Rightarrow y=(x-3)^2-4 \end{gathered}[/tex]
Solving for x,
[tex]\begin{gathered} \Rightarrow y+4=(x-3)^2 \\ \Rightarrow\pm\sqrt{y+4}=x-3 \\ \Rightarrow x=\pm\sqrt{y+4}+3 \end{gathered}[/tex]
Then, set y=-3 and find the corresponding value of x, as shown below
[tex]\begin{gathered} y=-3 \\ \Rightarrow x=\pm\sqrt{-3+4}+3 \\ \Rightarrow x=\pm\sqrt{1}+3 \\ \Rightarrow x=2,4 \end{gathered}[/tex]
Thus, the two answers are x=2, and x=4.
