Jaden's work is shown below. Explain the mistake in his work. Help Jaden to fix his mistake.
(5x2-3x + 1) - (2x2 - 4x - 2)
= 5x²-3x + 1-2x² - 4x - 2
= 5x² - 2x²-3x - 4x +1-2
= 3x² - 7x -1​