`A = (3x + 2)^2 + 2(2 + 3x)(1 - 2x) + (2x - 1)^2`
`= 9x^2 + 12x + 4 + 2 . (2 - 4x + 3x - 6x^2) + 4x^2 - 4x + 1`
`= 9x^2 + 12x + 4 + 4 - 8x + 6x - 12x^2 + 4x^2 - 4x + 1`
`= (9x^2 - 12x^2 + 4x^2) + (12x - 8x + 6x - 4x) + 9`
`= x^2 + 6x + 9`
`B = (5x + 5)^2 + 10(x - 3)(3 + x) - (x + 3)^3`
`= 25x^2 + 50x + 25 + 10 . (x^2 - 9) - x^3 + 9x^2 + 27x + 27`
`= 25x^2 + 50x + 25 + 10x^2 - 90 - x^3 + 9x^2 + 27x + 27`
`= -x^3 + (25x^2 + 10x^2 + 9x^2) + (50x + 27x) - 38`
`= -x^3 + 44x^2 + 77x - 38`
Gửi bạn nha
