Question

1 (x-3) (x^2+3x+9)

2 (x+4) (x^2+4x+16)

3. (x-3y) (x^2+3xy+9y^2)   hằng đẳng thức

Answer 1

sửa đề \(\left(x+4\right)\left(x^2-4x+16\right)\)

Cái này lm r mak

Answer 2

`[38]`

Ta có: `a^3 + b^3 = (a+b)(a^2-ab+b^2)`

`a^3 - b^3 = (a-b)(a^2+ab+b^2)`

`a, = x^3 - 3^3 = x^3 - 27``

`b, = x^3 + 4^3 = x^3 + 64` Sửa thành `x^2 - 4x + 16`

`c, = x^3 - (3y)^3 = x^3 - 27y^3`

Answer 3

\(1,\left(x-3\right)\left(x^2+3x+9\right)=x^3-3^x=x^3-27\)

\(2,\left(x+4\right)\left(x^2+4x+16\right)\)

\(=x\left(x^2+4x+16\right)+4\left(x^2+4x+16\right)\)

\(=x^3+4x^2+16x+4x^2+16x+64\)

\(=x^3+8x^2+32x+64\)

\(3,\left(x-3y\right)\left(x^2+3xy+9y^2\right)=x^3-\left(3y\right)^3=x^3-27y^3\)