Question

The pupil said,"where have i made a mistake"?

Answer 1

Heya
Here is your answer
_____________________________________________________________

The pupil asked where he had made a mistake

Have is changed into had....
In interrogative sentences asked is used instead that
As there was a question word where it would be kept as it is without changing into if or whether
_____________________________________________________________

Hope it helps! ^_^

Answer 2

Heya!

Seems like we need to change it's narration? If it is, here's your answer -

Sentence - The pupil said, "Where have i made a mistake?"

Reported speech - The pupil asked where he had made a mistake.

Hope it helps!