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1-(x-3)/(x-1)怎样变成2/(x-3)?

题目详情
1-(x-3)/(x-1)怎样变成2/(x-3)?
▼优质解答
答案和解析
先通分:把1变为(x-1)/(x-1),再根据分式相减的原理,(分母不变,分子相减),用(x-1)/(x-1)减去(x-3)/(x-1)得到:[(x-1)-(x-3)]/(x-1)=2/(x-1)
此时发现2/(x-1)与2/(x-3)只是分母不同,那就再用2/(x-1)乘以(x-1)/(x-3)
或者除以(x-3)/(x-1)就可以得到2/(x-3)
总的来说就是将原式1-(x-3)/(x-1)乘以(x-1)/(x-3)或者除以(x-3)/(x-1)就可以得到2/(x-3)了