"You haven't plugged in" is better.
Either works. "You haven't" is a more typically British phrasing.
You haven't is what it says. I have no idea why we're being given 'didn't' .Surely that would be tu n'as fait brancher?
No. English has confused you: we often use "did" as the negative auxiliary instead of "have". When there is no negative using "did" is emphatic. French does not use "faire" in the same manner as "did"; it uses "avoir/être" for both "did" and "have".
I'm a little confused, I'm assuming we are using the imperative for a command and brancher is a regular er verb, should it be branches, instead of branche?
Imperatives of 1st group verbs (infinitive ending in -er) lose the final -s in "tu" form.
"Tu manges." - "Mange !"
Why different places for 'in' in this sentence; 'You haven't plug the computer in, plug it in' marked wrong.
Your placement of "in" is fine in both cases, but it should be "You haven't plugged..."
Someone else in the comments said, 'Haven't' is more british english, but is also fine in this case
Didn't = Haven't
The three forms of imperative are tu nous and vous. In this sentence someone is being told to plug it in, therefore we should use the imperative.
I find the squeaky voice of this character so maddening it almost make me want to leave Duolingo. It is unbearable.
It's no good saying we should have put "not" in the answer when the only choice was "'nt"!!!