2x + 3y = 5
3y = 5 - 2x 

Add +2x to both sides of the second equation:

   3y = 5 - 2x 
  +2x      +2x
  ------------
3y+2x = 5

Swap the terms on the left side:

2x+3y = 5

So the system of equations is:

2x + 3y = 5
2x + 3y = 5

Multiply the second equation through by -1
and add the two equations vertically
term by term:

 2x + 3y =  5
-2x - 3y = -5
-------------
  0 -  0 =  0
       0 =  0

When attempting to solve a system of equations, 
if all the variable terms cancel, leaving only
purely numeric terms, then if the purely
numeric equation is true, the system of 
equations is dependent, and if the purely
numeric equation is false, the system of 
equations is inconsistent.

Since the purely numeric equation 0 = 0 is
true, the system is dependent.

Edwin