Thực hiện phép tính: (3x – 4)(2x + 1) – (x – 2 )(6x + 3) =
Giải thích
(3x – 4)(2x + 1) – (x – 2 )(6x + 3) = (3x.2x – 4.2x + 3x – 4) – (6x.x – 6x.2 + 3x – 3.2)
= ( 6x2 – 8x + 3x – 4 ) – ( 6x2 – 12x + 3x – 6 )
= ( 6x2 – 5x – 4 ) – ( 6x2 – 9x – 6 )
= 6x2 – 5x – 4 – 6x2 + 9x + 6
= 4x + 2