求分式方程中字母值(或范围)的方法

• 作 者: 范子坚
• 机 构: 江苏
• 出 处: 中学课程辅导(初二版)
• 发表日期: 2004年12期
• 关键词: 最简公分母 增根 整式方程 中含 十一公 解方程

在求分式方程中字母值或范围时,不少同学常发生错误,下面举例说明其解法.例1 a为何值时,解分式方程3/x-2+3/x-1=a/x2-3x+2会产生增根? 分析:因为最简公分母是(x-1)(z-2),所以当求得的解是x=1或x=2时,即为方程的增根,因原方程会产生增根,所以先将分式方程转化为整式方程,把整式方程的根求出来,这个根中含字母a,把x=1,x=2分别代人,就能求得a的值. 解:方程两边都乘(x-1)(x-2),约去

In the calculation of the letter value or range in fractional equations, many students often make mistakes. Here is an example of the solution. Example 1 a What is the value of solution fractional equation 3/x-2+3/x-1=a/ X2-3x+2 generates rooting? Analysis: Since the simplest common denominator is (x-1)(z-2), when the solution is x=1 or x=2, it is the increase of the equation. Root, because the original equation will produce rooting, so the first fractional equation is converted into a whole equation, the root of the whole equation is obtained, this root contains the letter a, x=1, x=2 respectively, it can be found Get the value of a. Solution: The equation is multiplied by (x-1)(x-2) on both sides.