Answer/Step-by-step explanation:

(3x² - 8x + 7) - (5x² + 2x - 3)

= 3x² - 8x + 7 - 5x² - 2x + 3 (distributing the negative sign)

= (3x² - 5x²) + (-8x - 2x) + (7 + 3) (grouping like terms)

= -2x² - 10x + 10

Therefore, the answer is -2x² - 10x + 10.