Compare your answers:

• The tables don't say “input” and “output.”
• While there is a column labeled $x$, there is not a column labeled $y$.
• One function is called $f$. The other is called $g$.
• There’s an expression (rather than a number) on the right side of the equation $f(x)=10-2x$ and $g(x)=x^3$.
• If we substitute the values in the left column for the $x$ in the expression, we get the values in the right column.

Compare your answers:

• Why is $x$ on the right side of the equal sign?
• Are there rules about how to name functions?
• What does each equation, $f(x)=10-2x$ and $g(x)=x^3$, mean?