The other tutor doesn't know how to use the software efficiently.

First draw the graph of 

2y = 8

Divide both sides by 2

 y = 4

This is equivalent to

 y = 0x + 4  which is a line with 0 slope and y-intercept (0,4).
A line with slope = o is a horizontal line.  We draw it dotted 
because  the inequality is < not <.



Now we decide if we should shade above or below the line.  We 
shade below the line either because of what the other tutor said
or because we substitute the test point (0,0) in the original
inequality

  2y < 8
2(0) < 8
   0 < 8

That is true so we shade the side of the line that the origin is
on:  




Edwin

Maybe you meant to graph 2y<8 on a number line.  If so:

2y < 8

Divide both sides by 2

 y < 4

<=====================o---------
-3 -2 -1  0  1  2  3  4  5  6  7

or

<=====================)---------
-3 -2 -1  0  1  2  3  4  5  6  7

Edwin