The equation which is a function of x is x²=y.
Given an equation that is a function of x.
A function may be a relation between a collection of inputs and a collection of permissible outputs with the property that every input is said to precisely one output.
If we input a value of x then we get the output f(x) = y, which is the function of x.
We are given four options out of which we are to pick the one which may be a function of 'x'.
The first option is x=5 in which no term of y is included and its a constant. So, option 1 is not correct.
The second option is x=y²+9 in which y contains a power 2. So, option 2 is not correct.
The third option is x²=y in which y contains power 1. So, option 3 is correct.
The fourth option is x²=y²+16 in which y contains a power 2. So, option 3 is not correct.
Hence, the equation which is a function of x is x²=y.
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