Why does macbeth hire murderers to kill banquo and fleance?

Macbeth hires murderers to kill Banquo and Fleance because he sees them as threats to his own power. After being told by the witches that he will become king, Macbeth becomes obsessed with gaining and maintaining power. He is willing to do anything to protect his position, even if it means killing innocent people.

Banquo is a particularly dangerous threat to Macbeth because he is also aware of the witches' prophecies. Macbeth knows that Banquo suspects him of killing King Duncan, and he fears that Banquo may try to expose him. He also believes that Banquo's son, Fleance, is a potential rival for the throne.

By hiring murderers to kill Banquo and Fleance, Macbeth hopes to eliminate any potential threats to his power. He is ultimately successful in killing Banquo, but Fleance escapes. This proves to be a costly mistake, as Fleance later grows up to become a leader of the rebellion against Macbeth.