Đáp án:
`(x+2)(x+3)(x+4)(x+5)-24`
`=[(x+2)(x+5)][(x+3)(x+4)]-24`
`=(x^2+7x+10)(x^2+7x+12)-24`
`=(x^2+7x+11)^2-1-24`
`=(x^2+7x+11)^2-25`
`=(x^2+7x+11-5)(x^2+7x+11+5)`
`=(x^2+7x+16)(x^2+7x+6)`
`=(x^2+7x+16)(x^2+x+6x+6)`
`=(x^2+7x+16)[x(x+1)+6(x+1)]`
`=(x^2+7x+16)(x+1)(x+6)`.