Question 74204
You can just pick 2 numbers for x and plug them in to get 2 numbers of y (or f(x)). Lets let x=0 and x=1
{{{f(0) = -2(0)-5}}}
{{{f(0) = -5}}}
So our first point is (0,-5). Now lets plot our second point. Lets let x=1
{{{f(0) = -2(1)-5}}}
{{{f(0) = -2-5}}}
{{{f(0) = -7}}}  
So our second point is (1,-7). Lets plot these points and draw a line between them              
{{{drawing( 300, 300, -6, 5, -10, 10,

  grid( 1 ),
  locate(1,-7,Point(1,-7)),
  locate(0,-5,Point(0,-5)),
  circle(1,-7,.2),
  circle(0,-5,.2)
  

)}}}Connect the 2 dots to make a line
Now just connect the points with a ruler. 
{{{graph( 300, 200, -6, 5, -10, 10, -2x-5) }}}So here's what the graph looks like.