小明、小华、小颖三名同学解这样一个问题：求a为何值时，成立．小明：因为a2+2a﹣3=（a﹣1）（a+3），从分式的右边知，分式的分子和分母同时除以a﹣1，只需a﹣1≠0即可，故a的取值范围是-八年级

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