在各地的高考试题和模拟试题中,经常涉及多元变量的取值范围问题.这类试题常常因为减少变量方法具有很强的灵活性,以及产生不等的途径具有多样性,造成部分考生产生畏惧心理,止步不前.如何才能顺利解决此类问题呢?首先要学会消元,常用的消元法有整体换元、代入消元、三角换元等,其中所给条件若是多个变量的齐次等式(或齐次不等式),则先将其两边同 In the college entrance examination questions and mock exam questions all over the world, often involves the range of multivariate variables.These questions are often due to the variable flexibility of the variable method, as well as produce a diversity of ways, resulting in fear of some candidates Psychological, halt .How can we successfully solve such problems? First of all to learn to eliminate, commonly used elimination method as a whole for the yuan, into the consumer element, triangle for yuan, etc., where the conditions given if multiple variables Qi Sub-equation (or homogeneous inequality), then the first two sides of the same