Question

Which of the following describes the relationship between x and y for a line that has a slope of zero?
A. As x increases, y decreases.
B. As x increases, y increases.
C. As x increases, y remains the same.
D. As y increases, x remains the same.

Answer 1

When a line has zero slope, it is horizontal. You can see that a horizontal line ranges over all x values, but y never changes.

Therefore, C. as x increases, y remains the same, is the right answer.

This, of course, assumes you have labeled the horizontal axis of the Cartesian plane "x" and the vertical axis "y". In the opposite situation, choice D would be completely valid.

Answer 2

x is always 0