$A$ point $(x, y, z)$ moves parallel to the $x$-axis. Which of the three variables $x, y, z$ remain fixed?

Let $A, B, C$ be the feet of the perpendiculars from a point $P$ on the $xy, yz,$ and $zx$-planes respectively. Find the coordinates of $A, B, C$ for the following points $P$:
$(3, 4, 5), (-5, 3, 7), (4, -3, -5)$

If the sum of the squares of the distances of a point from the three coordinate axes is $36$,then its distance from the origin is:

From which of the following is the distance of the point $(1, 2, 3)$ equal to $\sqrt{10}$?

The coordinates of points $A, B, C, D$ are $(a, 2, 1), (1, -1, 1), (2, -3, 4)$ and $(a+1, a+2, a+3)$ respectively. If $AB = 5$ and $CD = 6$,then $a = $

Find the distance between the following pairs of points: $(-3, 7, 2)$ and $(2, 4, -1)$.