Thực hiện các phép tính sau: a) (5x^3 – 2x^2 + 4x – 4)(3x^2 + x – 1);

a) (5x³ – 2x² + 4x – 4)(3x² + x – 1)

= 3x²(5x³ – 2x² + 4x – 4) + x(5x³ – 2x² + 4x – 4) – 1(5x³ – 2x² + 4x – 4)

= 15x⁵ – 6x⁴ + 12x³ – 12x² + 5x⁴ – 2x³ + 4x² – 4x – 5x³ + 2x² – 4x + 4

= 15x⁵ + (–6x⁴ + 5x⁴) + (12x³ – 2x³ – 5x³) + (–12x² + 4x² + 2x²)+ (–4x– 4x) + 4

= 15x⁵ – x⁴ + 5x³ – 6x² – 8x + 4