3x + y - 1 = 0
Cynthia, the first thing you need to do is find the slope of the line that you are given. To do this point the equation in slope intercept form (y=mx+b). In order to do this you would need to subtract the 3x from the left to the right and add the one from the left to the right. Hence, you would have y = -3x + 1. Because "m" represents our slope we know that slope of this line is -3.
Using the information from above and the fact that parallel lines have equal slopes the slope of a line parallel would also be -3. Hope this helps!