Try replacing the 5 with C. Or drop it altogether.
My work is attached. And here is the work shown by Wolfram Alpha: integral 2/(xln(8x - Wolfram|Alpha))
I also attached a screen shot of what I am doing in terms of inputting my answer to the computer system. The letter C is not defined and I tried constants such as 5 and 0. I also tried not entering a constant.
Am I making a stupid mistake?