Rút gọn biểu thức: (7x - 3)(2x + 1)
Giải thích
(7x – 3)(2x + 1) – (5x – 2)(x + 4) – 9x2 + 17x
= 14x2 – 6x + 7x – 3 – 5x2 – 20x + 2x + 8 – 9x2 + 17x
= 5
(7x – 3)(2x + 1) – (5x – 2)(x + 4) – 9x2 + 17x
= 14x2 – 6x + 7x – 3 – 5x2 – 20x + 2x + 8 – 9x2 + 17x
= 5