Ok, so when it says "3x, x
2," it means that when the x value is less than or equal to 3, you graph 3x. You would have the following points on the line: (-3,-9), (-2,-6), (-1,-3), (0,0), (1,3), and (2,6). The endpoint of the ray on the left side (the points I just said) would be (2,6)
When it says, "1/2 x +5, 2
x," it means that when the value of x is greater than or equal to 2, the y value is .5x + 5. You would graph the following points: (2,6), (4,7), (6,8), and (8,9). The endpoint of th ray on the right (the points I just said) would be (2,6).
Keep in mind that though the graph is continuous, it isn't one line, but 2 rays (which you probably already know).