对于一些看起来较复杂的分式方程,我们可应用增元法(即增设一个未知数)巧妙求解.现举例说明如下:例1解方程:x2+81x2(9+x)2=40.分析本题如去分母求解,将会得到一个较复杂的一元四次方程,显然对初中学生来说有一定难度.因此,需要寻求一定的技巧.注意到81x2(9+x)2=99+xx2,所以若增 For some seemingly complicated fractional equations, we can apply the incremental method (that is, add an unknown number) to solve it cleverly. Now illustrate as follows: Example 1 Solution equation: x2+81x2(9+x)2=40. If you solve the denominator, you will get a more complex equation of quartic equation. Obviously it is difficult for junior high school students. Therefore, you need to seek certain skills. Note that 81x2(9+x)2=99+xx2, so If increased