$x^3-7x-6$$=x^3-4x-3x-6$$=x(x^2-4)-(3x+6)$ $=x(x^2-2^2)-(3x+6)$ $=x(x+2)(x-2)-3(x+2)$$=(x+2){[x(x-2)]-3}$$=(x+2)(x^2-2x-3)$$=(x+2)(x+1)(x-3)$ Reply
Đáp án: `x^3 – 7x – 6``= (x^3 – x) – (6x + 6)``= x.(x^2 – 1) – 6(x + 1)``= x(x – 1)(x + 1) – 6(x+ 1)``= (x + 1)(x^2 – x – 6)` `= (x + 1)[(x^2 + 2x) – (3x + 6)]` `= (x + 1)[x(x + 2) – 3(x+ 2)]` `= (x + 1)(x+ 2)(x – 3)` Giải thích các bước giải: Reply
$x^3-7x-6$
$=x^3-4x-3x-6$
$=x(x^2-4)-(3x+6)$
$=x(x^2-2^2)-(3x+6)$
$=x(x+2)(x-2)-3(x+2)$
$=(x+2){[x(x-2)]-3}$
$=(x+2)(x^2-2x-3)$
$=(x+2)(x+1)(x-3)$
Đáp án:
`x^3 – 7x – 6`
`= (x^3 – x) – (6x + 6)`
`= x.(x^2 – 1) – 6(x + 1)`
`= x(x – 1)(x + 1) – 6(x+ 1)`
`= (x + 1)(x^2 – x – 6)`
`= (x + 1)[(x^2 + 2x) – (3x + 6)]`
`= (x + 1)[x(x + 2) – 3(x+ 2)]`
`= (x + 1)(x+ 2)(x – 3)`
Giải thích các bước giải: