I have a book that shows A7 one way, whereas a Chord Chart I have shows it another way. The same goes for other chords. Why is this?
because you coulde arrange the notes in a different order and get a different sound they are called voicings btw
Because the notes repeat over the fretboard. This allows the chord to be played in different "voicings," they're called.
all A7 needs are the notes A, C#, E, and G and since the guitar is layed out in a matrix there are tons of ways to make the chord.
it's called an inversion. one may be more convenient to play in a certain situation