Đáp án + Giải thích các bước giải:
CT:
`(A±B)^2=A^2±2AB+B^2`
`A^2-B^2=(A-B)(A+B)`
`(A±B)^3=(A^3±3A^2B+3AB^2±B^3)`
`A^3±B^3=(A±B)(A^2{-+}AB+B^2)`
`a)x^2+4x+4=x^2+2.x.2+2^2=(x+2)^2`
`b)x^2-8x+16=x^2-2.x.4+4^2=(x-4)^2`
`c)(x+5)(x-5)=x^2-25`
`d)x^3+12x^2+48x+64=x^3-3.x^2.4+3.x.4^2-4^3`
`=(x-4)^3`
`e)x^3-6x^2+12x-8=x^3-3.x^2.2+3.x.2^2-2^3`
`=(x-2)^3`
`f)(x+2)(x^2-2x+4)=x^3+8`
`g)(x-3)(x^2+3x+9)=x^3-27`
`h)x^2+2x+1=(x+1)^2`
`i)x^2-1=(x-1)(x+1)`
`k)x^3+27=(x+3)(x^2-3x+9)`
