Đáp án: `x=1`.
Giải thích các bước giải:
`(x+1)(x+2)(x+5)-x^3-8x^2=27`
`<=>(x-1+2)(x+2)(x+5)-x^3-8x^2-27=0`
`<=>(x-1)(x+2)(x+5)+2(x+2)(x+5)-x^3-8x^2-27=0`
`<=>(x-1)(x^2+7x+10)+2x^2+14x+20-x^3-8x^2-27=0`
`<=>(x-1)(x^2+7x+10)-x^3-6x^2+14x-7=0`
`<=>(x-1)(x^2+7x+10)-x^3+x^2-7x^2+7x+7x-7=0`
`<=>(x-1)(x^2+7x+10)-x^2(x-1)-7x(x-1)+7(x-1)=0`
`<=>(x-1)(x^2+7x+10-x^2-7x+7)=0`
`<=>17(x-1)=0`
`<=>x-1=0`
`<=>x=1`.
Vậy `x=1`.
