90x^3-3(4x-2x (4x-3(5x^2-2)))

Đáp án `+` giải thích các bước giải:

`90x^3-3(4x-2x (4x-3(5x^2-2)))` `= 90x^3-3(4x-2x (20x^3 - 2x - 15x^2 + 6))`

`=90x^3-3(80x^4 - 8x^2 - 60x^3 + 24x - -4x^4 + 4x^2 + 30x^3 - 12x )`

`= 90x^3 - 3 ( [8x^4 - 4x^4] + [-60x^3 + 30x^3] + [ -8x^2 + 4x^2 ] + [ 24x - 12x ] )`

`= 90x^3 - 3 ( 4x^4 -30x^3 - 4x^2 + 12x )`

`= 360x^7 - 2700x^6 - 360x^5 + 1080x - 12x^4 - 90x^3 + 12x^2 - 36x`

`= 360x^7 - 2700x^6 - 360x^5 - 12x^4 - 90x^3 + 12x^2 + ( 1080x - 36x )`

`= 360x^7 - 2700x^6 - 360x^5 - 12x^4 - 90x^3 + 12x^2 + 1044x`