Question

1、(a的2次方-b的2次方分之a的2次方+2ab+b的2次方减a＋b分之a-b)÷a-b分之a＋b a=-1 b=2

2、y的4次方减x的4次方分之x的4次方y÷x的2次方＋y的2次方分之x的2次方减x＋y分之y的2次方÷（x分之y-1）

Answer 1

[(a²＋2ab＋b²)/(a²－b²)－(a－b)/(a＋b)]÷(a－b)/(a＋b)
＝{(a＋b)²/[(a－b)(a＋b)]－(a－b)/(a＋b)}×(a＋b)/(a－b)
＝(a＋b)/(a－b)×(a＋b)/(a－b)－(a－b)/(a＋b)×(a＋b)/(a－b)
＝(a＋b)²/(a－b)²－1
＝(-1＋2)²/(-1－2)²－1
＝-1/9－1
＝-10/9

x^4y/(y^4－x^4)÷x^2/(x^2＋y^2)－y^2/(x＋y)÷(y/x－1)
＝x^4y/[(y^2－x^2)(y^2＋x^2)]×(x^2＋y^2)/x^2－y^2/(x＋y)÷(y/x－x/x)
＝x^2y/(y^2－x^2)－y^2/(x＋y)÷(y－x)/x
＝x^2y/(y^2－x^2)－y^2/(x＋y)×x/(y－x)
＝x^2y/(y^2－x^2)－xy^2/(y^2－x^2)
＝(x^2y－xy^2)/(y^2－x^2)
＝xy(x－y)/[(y－x)(y＋x)]
＝-xy/(y＋x)