解
(x²-y²)/(x-y)²
=(x-y)(x+y)/(x-y)²
=(x+y)/(x-y)
x/a(x+2)與y/b(x+2)
∵最簡公分母為ab(x+2)
∴x/a(x+2)=xb/ab(x+2)
y/b(x+2)=ya/ab(x+2)約分：x的平方+xy除以（x+y)的平方通分：2xy除以（x+y)的平方與x除以x的平方-y的平方(x²+xy)/(x+y)²=x(x+y)/(x+y)²=x/(x+y)2xy/(x+y)²x/(x²-y²)∵最簡公分母為：(x+y)²(x-y)∴2xy/(x+y)²=2xy(x-y)/(x+y)²(x-y) x/(x²-y²)=x(x+y)/(x+y)²(x-y)不要兩個人都追問，謝謝