记x+2=t,
（x+1)^4+(x+3)^4-272
=(t-1)^4+(t+1)^4-272
=2t^4+12t^2-270
=2(t^2-9)(t^2+15)
=2(t-3)(t+3)(t^2+15)
=2(x-1)(x+5)(x^2+4x+19).
哦,是这样啊!那个人好厉害