macbeth characters

I'm reading Macbeth by Shakespeare, and I need to know what the most important scene in act 3 is.

at this point in the play Macbeth is justifying his killing of Duncan's guards to Macduff and the other thanes.

starting with this speech explore how shakespeare presents macbeth as duplicitous. Write about: How Shakespeare presents double dealing in this speech. How Shakespeare presents double dealing in the play as a whole

  What image does Shakespeare create of Macbeth BEFORE the audience first meet him in Act one Scene 3?

  Did Macbeth feel responsible for the death of King Duncan? Thank you