Có sai sót hay lỗi gì mong được góp ý ạ, mình không chắc lắm ạ:
`a.x^3+3x^2+3x+1`
`=x^2+3x^2. 1+3.x. 1^2+1^3`
`=(x+1)^3`
`b.x^3+6x^2+12x+8`
`=x^3-3.x^2. 2+3.x. 2^2+2^3`
`=(x+2)^3`
`c.27x^3+27x^2+9x+1`
`=(3x)^3+3.(3x)^2. 1+3.3x. 1^2+1^3`
`=(3x+1)^3`
`d.8x^3+12x^2y^2+6xy^4+y^6`
`=(2x)^3+3. (2x)^2. y^2+3. 2x. (y^2)^2+(y^2)^3`
`=(2x+y^2)^3`
`e.x^3-6x^2+12x-8`
`=x^3-3.x^2. 2+3.x. 2^2-2^3`
`=(x-2)^3`
`f.8x^3-60x^2+150x-125`
`=(2x)^2-3. (2x)^2. 5+3.2x. 5^2-5^3`
`=(2x-5)^3`
`g.x^3-6x^2y+12xy^2-8y^3`
`=x^3-3. x^2. 2y+3.x. (2y)^2-(2y)^3`
`=(x-2y)^3`
`h.x^3-9x^2+27x-27`
`=x^3-3. x^2. 3+3.x. 3^2-3^3`
`=(x-3)^3`
Áp dụng hằng đẳng thức:
`(a+b)^3=a^3+3a^2b+3ab^2+b^3`
`(a-b)^3=a^3-3a^2b+3ab^2-b^3.`
