多项式除以单项式~1,利用乘法公式计算：[(a-b)²+4ab]/(a+b)²2,(a^4-b^4)

1,[(a-b)²+4ab]/(a+b)²
=[a^2-2ab+b^2+4ab]/(a+b)^2
=(a+b)^2/(a+b)^2
=1
2,(a^4-b^4)/(a+b)/(a^2+b^2)
=(a^4-b^4)/[(a+b)*(a^2+b^2)]
=[(a^2-b^2)*(a^2+b^2)]/[(a+b)*(a^2+b^2)]
=(a^2-b^2)/(a+b)
=(a-b)(a+b)/(a+b)
=a-b
3,(6a^n+3+12a^n+2-3a^n)/3a^n-2
=3a^n-2 (2a^5+4a^4-3a^2)/3a^n-2
=2a^5+4a^4-3a^2