(X-3)(x+3)(x+2)-(x-1)(x^2-3)-5x (x+4)^2-(x-5)^2 03/07/2021 Bởi Amaya (X-3)(x+3)(x+2)-(x-1)(x^2-3)-5x (x+4)^2-(x-5)^2
Đáp án: `(x-3)(x+3)(x+2)-(x-1)(x^2-3)-5x(x+4)^2-(x-5)^2` `=(x^2-9)(x+2)-(x-1)(x^2-3)-5x(x^2+8x+16)-(x^2-10x+25)` `=x^3+2x^2-9x-18-(x^3-x^2-3x+3)-(5x^3+40x^2+16x)-x^2+10x-25` `=(x^3-x^3+5x^3)+(2x^2+x^2-40x^2-x^2)+(-9x+3x-16x+10x)+(-18-3-25)` `=-5x^3-38x^2-12x-46.` Bình luận
`(x – 3)(x + 3)(x + 2) – (x – 1)(x^2 – 3) – 5x(x + 4)^2 – (x – 5)^2` `= (x^2 – 9)(x + 2) – (x^3 – 3x – x^2 + 3) – 5x(x^2 + 8x + 16) – (x^2 – 10x + 25)` `= (x^3 + 2x^2 – 9x – 18) – x^3 + 3x + x^2 – 3 – 5x^3 – 40x^2 – 80x – x^2 + 10x – 25` `= (x^3 – x^3 – 5x^3) + (2x^2 + x^2 – 40x^2 – x^2) – (9x + 80x – 10x) – (18 + 3 + 25)` `= -5x^3 – 38x^2 – 79x – 46` Bình luận
Đáp án:
`(x-3)(x+3)(x+2)-(x-1)(x^2-3)-5x(x+4)^2-(x-5)^2`
`=(x^2-9)(x+2)-(x-1)(x^2-3)-5x(x^2+8x+16)-(x^2-10x+25)`
`=x^3+2x^2-9x-18-(x^3-x^2-3x+3)-(5x^3+40x^2+16x)-x^2+10x-25`
`=(x^3-x^3+5x^3)+(2x^2+x^2-40x^2-x^2)+(-9x+3x-16x+10x)+(-18-3-25)`
`=-5x^3-38x^2-12x-46.`
`(x – 3)(x + 3)(x + 2) – (x – 1)(x^2 – 3) – 5x(x + 4)^2 – (x – 5)^2`
`= (x^2 – 9)(x + 2) – (x^3 – 3x – x^2 + 3) – 5x(x^2 + 8x + 16) – (x^2 – 10x + 25)`
`= (x^3 + 2x^2 – 9x – 18) – x^3 + 3x + x^2 – 3 – 5x^3 – 40x^2 – 80x – x^2 + 10x – 25`
`= (x^3 – x^3 – 5x^3) + (2x^2 + x^2 – 40x^2 – x^2) – (9x + 80x – 10x) – (18 + 3 + 25)`
`= -5x^3 – 38x^2 – 79x – 46`