Giải thích các bước giải:
Bài `1.`
`a)`
`A=x^8-1`
`A=(x^4)^2-1`
`A=(x^4-1)(x^4+1)`
`A=[(x^2)^2-1^2](x^4+1)`
`A=(x^2-1)(x^2+1)(x^4+1)`
`A=(x-1)(x+1)(x^2+1)(x^4+1)`
`b)`
`B=x^2+22x+121`
`B=x^2+2.x.11+11^2`
`B=(x+11)^2`
`c)`
`C=x^2-x+1/4`
`C=x^2-2.x . 1/2+(1/2)^2`
`C=(x-1/2)^2`
`d)`
`D=x^3+6x^2+12x+8`
`D=x^3+3.x^2.2+3.x.2^2+2^3`
`D=(x+2)^3`
Bài `2.`
`a)`
`M=27x^3-27x^2+9x-1`
`M=(3x)^3-3.(3x)^2 . 1+3.3x.1^2-1^3`
`M=(3x-1)^3`
`b)`
`N=x^3+125`
`N=x^3+5^3`
`N=(x+5)(x^2-5x+5^2)`
`N=(x+5)(x^2-5x+25)`
`c)`
`P=8x^3-1`
`P=(2x)^3-1^3`
`P=(2x-1)[(2x)^2+2x.1+1^2]`
`P=(2x-1)(4x^2+2x+1)`