解
(56x³yz^4)/(48x^5y²z)
=(7x²z³)/(6x^4y)——約去8xyz
(x²-9)/(x²-2x-3)
=(x-3)(x+3)/(x-3)(x+1)——約去(x-3)
=(x+3)/(x+1)那這一題怎樣計(jì)算？1/（x-1）-x/（x²-1）1/(x-1)-x/(x²-1)=(x+1)/(x²-1)-x/(x²-1)——第一個式子分子分母上下乘以(x+1)=(x+1-x)/(x²-1)=1/(x²-1)有其他問題采納后求助，謝謝