问题
解答题
计算化简：
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答案
原式=
+x (x+2)(x+1)
+x (x+2)(x-1) 2 (1+x)(1-x)
=
+x(x-1) (x+2)(x+1)(x-1)
-x(x+1) (x+2)(x+1)(x-1) 2(x+2) (x+2)(x+1)(x-1)
=x2-x +x2+x-2x-4 (x+2)(x2-1)
=2x2-2x-4 (x+2)(x+1)(x-1)
=2(x-2)(x+1) (x+2)(x+1)(x-1)
=
．2x-4 x2+x-2