Gazebo 9.0 Launching Issue

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I have installed ros-melodic-gazebo9 in my desktop. It was successfully installed. When I am writing "gazebo" command to launch it, I am not able to launch. It is showing me error at sometime or sometimes nothing is happening. I am using Ubuntu 18.04 bionic and my desktop has "Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz". I have attached screenshot of the same. Please help me out.

Thanks in advance.