关于分式的运算,现总结几点解题思路, 以供参考. 一、认真观察,巧妙变形例1 若xy=a,xz=b,yz=c,且abc≠0, 求x2+y2+z2的值. 分析:要想求出x2+y2+z2的值,须先求出x2、y2、z2,通过认真分析,观察,三个已知等式相乘时有x2y2z2=abc,再结合三个已知等式,可找出x2、y2、z2和已知量a、b、c之间的关系. With respect to fractional operations, we now summarize a few ideas for problem solving for your reference. 1. Careful observation, clever modification example 1 If xy=a, xz=b, yz=c, and abc≠0, find x2+y2+ The value of z2. Analysis: In order to find the value of x2 + y2 + z2, we must first find x2, y2, z2. Through careful analysis, observe that there are x2y2z2 = abc when the three known equations are multiplied. Three known equations find the relationship between x2, y2, z2 and known quantities a, b, c.