﹙(a^2)(b^4)﹚^n＋3﹙﹣a(b^2)﹚^2n＋﹙﹣2(a^n)(b^2n)﹚^2
＝(a^2n)(b^4n )＋3(a^2n)(b^4n )＋4(a^2n)(b^4n)
＝8(a^2n)(b^4n)