I’ve found several math errors in videos. What you can do if you’re using the website version of Khan Academy is to go into what I think is called Discussion for the video. (This is where users can, for example, ask questions about the content if they don’t quite understand it and can then possibly get a clarification/explanation on the topic.) Errors in videos can also be pointed out in the Discussion. I don’t think videos are redone just to correct these errors, but seeing that others have posted corrections, which then may lead to a new solution or a better clarification of the material is helpful.

I’ve found that since most videos have been available here for quite a while, all of the errors I’ve found have already been reported in the Discussion by someone else.

Unfortunately, if you are using Khan Academy in a mobile app, you don’t have access to Discussion. But what you can do, and what I do, is to go to Khan Academy in your platform’s web browser, navigate to the same video, and go into the Discussion with it.

Hi Neil,

Thanks for reporting this!

Like Regina said, it's best to report video mistakes directly on the videos themselves in the future.

I, however, don't believe this particular issue is an error. In this problem, "C" represents all real constants. -2 times all real constants is still all real constants, so it is not necessary to write -2C, you can just write C.