分式的计算题(简单)2(X²-1)(X²-2X+1) (A+B)²-C²1,------------------------ 2,-----------------------(1-X)(X+1)² A²-(B-C)²
问题描述:
分式的计算题(简单)
2(X²-1)(X²-2X+1) (A+B)²-C²
1,------------------------ 2,-----------------------
(1-X)(X+1)² A²-(B-C)²
答
①2(X²-1)(X²-2X+1)/(1-X)(X+1)²
=2(x-1)(x+1)(x-1)^2 / [-(x-1)(x+1)^2]
= -2(x-1)^2/(x+1)
②
[(A+B)²-C²] / [A²-(B-C)²]
=[(A+B+C)(A+B-C)] / [(A-B+C)(A+B-C)]
=(A+B+C) / (A-B+C)
答
2(x²-1)(x²-2x+1)/(1-x)(x+1)²
=2(x-1)³(x+1)/(1-x)(x+1)²
=-2(x-1)²/(x+1)
[(a+b)²-c²]/{a²-(b-c)²]
=(a+b+c)(a+b-c)/(a-b+c)(a+b-c)
=(a+b+c)/(a-b+c)