we are given
[tex]x^2+y^2 =25[/tex]
We can solve for y
step-1: Subtract both sides by x^2
[tex]x^2+y^2-x^2 =25-x^2[/tex]
[tex]y^2 =25-x^2[/tex]
step-2: take sqrt both sides
[tex]\sqrt{y^2} =\sqrt{25-x^2}[/tex]
[tex]y =\sqrt{25-x^2}[/tex]
so, it is function on restricted intervals
so, we can get function as
[tex]y =\sqrt{25-x^2}[/tex]
or
[tex]y =-\sqrt{25-x^2}[/tex]..............Answer