Precalculus (6th Edition) Blitzer

no solution, $\emptyset$
Step 1. Inspect the inequality; we can find that the left side is a perfect square which will be larger or equal to zero. Step 2. The right side is $-1$, which is less than zero. Step 3. We can conclude that there is no solution to the inequality; in other words, the solution is an empty set $\emptyset$