I don't understand how the answer is "x is greater than or equal to 0." I already solved it algebraically but don't see how the answer is x > 0. Please show me how to get that answer.

Note: The book is not wrong, the teacher said it was a trick question and the answer is x is greater than or equal to 0. But we must show work on how to get that.

http://i46.tinypic.com/2h6y0sp.jpg

Thank you.