Determine whether the equation represents $y$ as a function of $x$.

$$16 x-y^4=0$$

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A relation that assigns to each element $x$ from a set of inputs, or $\underline{\hspace{1.5cm}}$ , exactly one element $y$ in a set of outputs, or $\underline{\hspace{1.5cm}}$, is called a $\underline{\hspace{1.5cm}}$.

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Two functions $f$ and $g$ can be combined by the arithmetic operations of $\underline{\hspace{1.5cm}},$ $\underline{\hspace{1.5cm}},$ $\underline{\hspace{1.5cm}},$ and $\underline{\hspace{1.5cm}},$ to create new functions.

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Two techniques for fitting models to data are called direct $\underline{\hspace{1.5cm}}$ and least squares $\underline{\hspace{1.5cm}}$.

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Two functions $f$ and $g$ can be combined by the arithmetic operations of $\underline{\hspace{1.5cm}},$ $\underline{\hspace{1.5cm}},$ $\underline{\hspace{1.5cm}},$ and $\underline{\hspace{1.5cm}},$ to create new functions.