Answer: The answer is (c) x² = y.
Step-by-step explanation: We are given four options out of which we are to select the one which is a function of 'x'.
To be a function of 'x', the equation must involve 'y to the power 1' only.
The first option is
[tex]x=5,[/tex] which is constant and so this option is incorrect.
The second option is
[tex]x=y^2+9,[/tex] which is incorrect because it involves y².
The third option is
[tex]x^2=y,[/tex] which is correct because it involves a single power of y.
The fourth option is
[tex]x^2=y^2+16,[/tex] which is also incorrect because it involves y².
Thus, (c) x² = y is the correct option.
