Câu `1:`
`-5x (x-3) + (x+3) + (x+1)^3 - (x-2)^3 + (x-1)(x^2 + x + 1)`
` = -5x . x + 5x . 3 + (x+3) + (x^3 + 3 . x^2 . 1 + 3 . x . 1^2 + 1^3) - (x^3 - 3 . x^2 . 2 + 3 . x . 2^2 - 2^3) + (x-1)(x^2 + x . 1 + 1^2) `
` = -5x^2 + 15x + x + 3 + (x^3 + 3x^2 + 3x + 3) - (x^3 - 6x^2 + 12x - 8) + (x^3 - 1^3)`
` = -5x^2 + 15x + x + 3 + x^3 + 3x^2 + 3x + 3 - x^3 + 6x^2 - 12x + 8 + x^3 - 1`
` = (x^3 - x^3 + x^3) + (-5x^2 + 3x^2 +6x^2) + (15x + x + 3x - 12x) + (3+3+8-1)`
` = x^3 + 4x^2 + 7x + 13`
Câu `2:`
`(x+5)(x^2 - 5x + 25) - (x+3)^3 + (x-2)(x^2+ 2x+4) - (x-1)^3`
` = (x+5)(x^2 - x . 5 + 5^2) - (x^3 + 3 . x^2 . 3 + 3 . x . 3^2 + 3^3) + (x-2)(x^2 + x . 2 + 2^2) - (x^3 - 3 . x^2 . 1 + 3 . x . 1^2 - 1^3)`
` = (x^3 + 5^3) - (x^3 + 9x^2 + 27x + 27) + (x^3 - 2^3) - (x^3 - 3x^2 + 3x - 1)`
` = x^3 + 125 - x^3 - 9x^2 - 27x -27 + x^3 - 8 - x^3 + 3x^2 - 3x + 1`
` = (x^3 - x^3 + x^3 - x^3) + (-9x^2 + 3x^2) + (-27x - 3x) + (125 - 27 - 8 +1)`
` = -6x^2 - 30x + 91`