分式求值同题是初中数学的重要内容.分式的形式多样,我们在解答此类问题时,要有灵活的解题策略,才能快速、准确地求解,下面举例说明.例1已知x/(x~2+x+1)=-2,求x~2/(x~4+x~2+1)的值.解析取已知等式的倒数,有(x~2+x+1)/x=-1/2,即x+1/x=-3/2.再取所求值的倒数,得 Fractional evaluation of the same problem is an important part of junior high school mathematics .Fractional forms, we have to answer such questions, we must have a flexible problem-solving strategy, in order to quickly and accurately solve, as an example. Find the value of x ~ 2 / (x ~ 4 + x ~ 2 + 1) from x / (x ~ 2 + x + 1) = - 2. Analyze the reciprocal of the known equation with (x ~ 2 + x +1) / x = -1 / 2, that is, x + 1 / x = -3/2.