3道初二数学题（关于分式的）
\u521d\u4e8c\u6570\u5b66\u5206\u5f0f\u4e60\u9898\u4ece\u4e66\u4e0a\u627e\u5427
\u2235a+(1/a)=5/2
\u2234[a+(1/a)]²=25/4
\u5373a²+2+1/a²=25/4
\u5f97a²+1/a²=17/4
\u2235(a-1/a)²=a²-2+1/a²=17/4-2=9/4
\u2234a-1/a=\u6b63\u8d1f3/2
=(2m^2-n^2)/(m^2-n^2)
上下同除以n^2即可求出：原式=41/16
2. x加上x分之1等于2，将等式两边平方即可求出：x平方+x平方分之1=2
3. 3x-4=(x-2)+2(x-1)
（x-1)(x-2)分之3x-4=1/(x-1) + 2/(x-2)
A=1 B=2
第一题，没做出来，一楼的好象不对吧，那个都除N方就消去好多数，然后就得1了，纳闷ing
第二题你把X+1/X=2平方，然后就得到X方+1/X方+2=4，移一下项就得到X方+1/X方=2
第三题，把等式右边通分，分母为（X-1)(X-2),得到分子为AX-A-BX-2B，因式分解一下，得到分子为(A-B)X-(A-2B),而等式左边分子为3X-4，所以，得到方程组A-B=3 A+2B=4最后解得A=1/3 B=10/3。（感觉数麻烦，是不是题抄错了？？？）
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