By inspection, and numerically. There appear to be two solutions. One is zero, which you can see by inspection. The other is approximately 7.57736, which you can get by a numerical routine. Here is WolframAlpha's answer.
By inspection, and numerically. There appear to be two solutions. One is zero, which you can see by inspection. The other is approximately 7.57736, which you can get by a numerical routine. Here is WolframAlpha's answer.