﹙x²＋4x＋8﹚²＋3x﹙x²＋4x＋8﹚＋2x²
设x^2+4x+8=a
则原式=a^2+3ax+2x^2
=(a+2x)(a+x)
=(x^2+6x+8)(x^2+5x+8)