Respuesta :

[tex]y=9-x^{2},\ x\ge0[/tex]

Reverse [tex]x[/tex] and [tex]y[/tex]:
[tex]x=9-y^{2},\ y\ge0[/tex]
Solve for [tex]y[/tex]:
[tex]x=9-y^{2}[/tex]
[tex]\rightarrow y^{2}=9-x[/tex]
[tex]\rightarrow y=\sqrt{9-x}[/tex] since [tex]y\ge0[/tex]