The equation of a line can be expressed in the form
#y=mx+b#
The #y# is the dependent variable, because it's value depends on the independent variable #x#. Also, #m# is the slope of the line, and #b# is the intercept point . The slope, if the line is drawn on a Cartesian graph, is a measure of the "steepness" of that line. Positive values of #m# go "uphill" from left to right and negative values go "downhill" from left to right. Larger #m# values get closer and closer to a vertical line, where as the closer #m# gets to zero, the more horizontal it gets.
In your case, #y=2x-5#, the value #m# is replaced by a #2#, so the slope is #2#. On a graph, it would look like this:
graph{y=2x-5[-2,5,-7,5]}