分式的约分18(b-a)2(2是指平方）/24(a-b)如何变成3(a-b)/4?(x+y)2(指平方)-10(x+y)+25/(x+y)2(指平方)-25如何变成x+y-5/x+y+5?[(x+y)^2-10(x+y)+25]/[(x+y)^2-25]
问题描述：
分式的约分
18(b-a)2(2是指平方）/24(a-b)如何变成3(a-b)/4?
(x+y)2(指平方)-10(x+y)+25/(x+y)2(指平方)-25如何变成x+y-5/x+y+5?
[(x+y)^2-10(x+y)+25]/[(x+y)^2-25]
答
(b-a)=-(a-b)
(b-a)^2=(a-b)^2
答
18(b-a)2(2是指平方）/24(a-b)如何变成3(a-b)/4?(b-a)^2=(a-b)^2所以18(b-a)^2/[24(a-b)]=3(a-b)/4分子分母同去6(a-b)[(x+y)^2-10(x+y)+25]/[(x+y)^2-25]=(x+y-5)^2/[(x+y+5)(x+y-5)]=(x+y+5)/(x+y-5)...