Use the figure of the coordinate axes to describe the set of
     Use the figure of the coordinate axes to describe the set of points (x, y, z) defined by the equations.  x = 8 and y = 4  Choose the correct answer below.  x = 8 and y = 4 is the set of all points of the form (x, 8, 4), a line parallel to the x-axis.  x = 8 and y = 4 is the set of all points of the form (8, 4, z), a line parallel to the z-axis.  x = 8 and y = 4 is the set of all points of the form (8, y, 4), a line parallel to the v-axis. 
  
  Solution
Set of all the point whoze x and y coordinates are fixed and equal to 8 and 4 respectively. Z coordinate can take any value. hence
(8,4, z)

