A horizontal line graph (parallel to the $x$-axis) represents the situation that:

A horizontal line graph (parallel to the $x$-axis) represents the situation that:
  1. $y$ changes uniformly with $x$
  2. $y$ remains constant as $x$ changes
  3. $x$ remains constant as $y$ changes
  4. $y$ doubles with every unit change in $x$

Solution

A horizontal line has slope $0$ and a constant $y$-value, so $y$ does not change as $x$ varies.

Asked in: IMO

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