hello everyone, i hope that u can help me in my problem. i am doing a analysis of a mechanism, code is shown below:

I will put you in context: I need to compare two graphs between a function called second derivative "xB" and a list called "gx" (this is an imported list). Individually everything is fine (I mean that the graphs of each one are fine) but when I want to draw these two lists with the command and ListLinePlot [{gx, ax}] the program shows me the following error: really i dont know how can i solve this error, I would thank you very much if you can help me