Question 182003
You could sit and pick an x, then find the y and plot it but the 
fastest way to graph with this form is to find your x and y interepts.
The x intercept occurs when y=0.
{{{3x-y=-10}}}
{{{3x-0=-10}}}
{{{3x=-10}}}
{{{x=-10/3}}}
First point is (-10/3,0).
The y intercept occurs when x=0.
{{{3x-y=-10}}}
{{{3(0)-y=-10}}}
{{{-y=-10}}}
{{{y=10}}}
Second point is (0,10).
Graph those 2 points. You only need two points to define a line. 
{{{ drawing( 300, 300, -5, 5, -3, 12, grid(1),circle(0,10,.2),circle(-10/3,0,.2)) }}}
Then draw the line that goes through those two points. 

{{{ drawing( 300, 300, -5, 5, -3, 12, grid(1),circle(0,10,.2),circle(-10/3,0,.2),graph(300,300,-5,5,-3,12,3x+10)) }}}