Tính: ( 4x3 – 2x2 – 6 ) – ( x3 – 7x2 + x – 5 )

(4x³ – 2x² – 6) – (x³ – 7x² + x – 5)

= 4x³ – 2x² – 6 – x³ + 7x² – x + 5

= 4x³ – x³ – 2x² + 7x² – x – 6 + 5

= 3x³ + 5x² – x – 1