The inequality is .

Factor the equation .

.

.

Now, there are two ways that this product could be greater than zero (positive) - both factors are positive or both factors are negative.

Case 1: Both factors are positive.

The only condition that makes both true is .

Case 2: Both factors are negative.

The only condition that makes both true is .

Solution .

The solution set in the interval notation is .

Observe the graph the open circle means and are not include in the solution set.

Set notation: .

Interval notation: .