黄桂亮
幼苗
共回答了14个问题采纳率:92.9% 举报
方法如果因式分解等变形题的数字较大.可采用换元法.把大数字换成字母 设1999=a.则2000=(a+1).所以原式=根号[a(a+1)(a+2)(a+3)+1] =根号{[a(a+3)][(a+1)(a+2)]+1} =根号{[a^2+3a][a^2+3a+2]+1} =根号{[a^2+3a+1]^2-1+1} =根号{[a^2+3a+1]^2} =a^2+3a+1 =(a+1)^2+a =(1999+1)^2+1999 =4001999
1年前
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