题目

The problem of waste is becoming more and more common , so it must be controlled . Every day , a number of ___21___ goes uneaten (没吃) and ends up in the trash , while many people in developing countries cannot even ___22___ to have one meal every day . The next time you ___23___ to a delicious dinner , ask yourself , “How much food will I ___24___ eat ? ” If you think about only taking as much as you can ___25___ , it will help you cut down ___26____waste . The problem of waste ___27___all over the world . People often consume(消费) ___28___than they really need . This ofte阅读理解下列材料然后回答问题：解方程：x2-3|x|+2=0解：（1）当x≥0时，原方程化为x2-3x+2=0，解得：x1=2，x2=1（2）当x＜0时，原方程化为x2+3x+2=0，解得：x1=1，x2=-2．∴原方程的根是x1=2，x2=1，x3=1，x4=-2．请观察上述方程的求解过程，试解方程x2-|x|-2=0．