There are several ways to go about this.

1) You have three breaks in the Real Numbers. x = -1, x = 3, and x = 1/2. Simply try a value in each of the four regions so defined and you are done.

2) Notice that (x-3)^2 is never negative. The only way for this expression to be positive is for (x+1) and (2x-1) to have the same sign. Where is that?

In both cases, you will want to include the three break points, as the question includes "=0".