代数式的求值问题是历年来中考中一种极为常见的题型,现根据近几年的中考情况,介绍几种常用的求值方法,供参考. 一、利用非负数例1 (2000年新疆中考题)若x,y是实数,且满足|2x-3|+(y+1)2=0,则x+y=___. 解:由条件得2x-3=0,y+1=0,得x=3/2,y=-1, The algebraic equation evaluation problem is an extremely common type of problem in the middle school entrance examinations over the years. According to the conditions of recent examinations, several commonly used methods of evaluation are introduced for reference. First, the use of non-negative examples 1 (Xinjiang, 2000) Exam Questions) If x,y is a real number and satisfies |2x-3|+(y+1)2=0, then x+y=___. Solution: Get 2x-3=0,y+1=0 from the condition , get x=3/2, y=-1,