1) (1/2x+3).(2x^2-4x-6) 2) (-2/3x+3).(3x^2-6x+9) ae jỏi toán đâu lào dd coi 30/07/2021 Bởi Iris 1) (1/2x+3).(2x^2-4x-6) 2) (-2/3x+3).(3x^2-6x+9) ae jỏi toán đâu lào dd coi
` 1) ` ` (1/2 x + 3)(2x^2 – 4x – 6) ` ` = 1/2 x(2x^2 – 4x – 6) + 3(2x^2 – 4x – 6) ` ` = x^3 – 2x^2 – 3x + 6x^2 – 12x – 18 ` ` = x^3 – 2x^2 + 6x^2 – 12x – 3x – 18 ` ` = x^3 + 4x^2 – 15x – 18 ` ` 2) ` ` (-2/3 x + 3)(3x^2 – 6x + 9) ` ` = -2/3 x(3x^2 – 6x + 9) + 3(3x^2 – 6x + 9) ` ` = -2x^3 + 4x^2 – 6x + 9x^2 – 18x + 27 ` ` = -2x^3 + 4x^2 + 9x^2 – 6x – 18x + 27 ` ` = -2x^3 + 13x^2 – 24x + 27 ` Bình luận
` 1) `
` (1/2 x + 3)(2x^2 – 4x – 6) `
` = 1/2 x(2x^2 – 4x – 6) + 3(2x^2 – 4x – 6) `
` = x^3 – 2x^2 – 3x + 6x^2 – 12x – 18 `
` = x^3 – 2x^2 + 6x^2 – 12x – 3x – 18 `
` = x^3 + 4x^2 – 15x – 18 `
` 2) `
` (-2/3 x + 3)(3x^2 – 6x + 9) `
` = -2/3 x(3x^2 – 6x + 9) + 3(3x^2 – 6x + 9) `
` = -2x^3 + 4x^2 – 6x + 9x^2 – 18x + 27 `
` = -2x^3 + 4x^2 + 9x^2 – 6x – 18x + 27 `
` = -2x^3 + 13x^2 – 24x + 27 `