Question

What does the set of points whose $x$-coordinate is $0$ represent?

• A. $x$ axis; $y=0$
• B. $y$ axis; $x=0$
• C. $x$ axis; $x=0$
• D. $y$ axis; $y=0$

Answer 1

The correct option is B $y$ axis; $x=0$

The set of points with $x$-coordinate as $0$ can be represented as $(0,y)$, where the values of $y$ can be anything.

This means the points $(0,y)$ lie on such a line, which is NOT in the left or right of $y$ axis as the values of $x$ are always $0$ on that line. This happens only when the line is coinciding with the $y$-axis. Hence, the points with $x$-coordinate as $0$ lie on $y$ axis, which is also denoted as $x=0$.