Answer
The lines are identical.
Work Step by Step
To find out if graphs of equations are identical lines, parallel lines or lines intersecting at a single point you need to compare the slopes first. The slope is the value multiplied by x when the equation is in this form: y=mx+b
To this we need to transform the equations.
$3x+y=0 <=> y=-3x$
$2y=-6x <=> y=-3x$
If lines are parallel or identical they hav the same slope, if they do not and are therefore intersecting at a single point the slope is different. If transforming the equations shows that the equations are exactly the same the lines are identical