1、已知a=2006x+2007,b =2006x+2006,c=2006x+2005 , 求2a2+2b2+2c2+2ab+2bc+2ac (a2表示2的平方 其...

2025-05-21 14:41:38
推荐回答(2个)
回答1:

a=2006(x+1)+1, b=2006(x+1), c=2006(x+1)-1
原式=(a+b)2+(a+c)2+(b+c)2=(2006(x+1)+1+2006(x+1))2+(2006(x+1)+1+2006(x+1)-1)2+(2006(x+1)+2006(x+1)-1)2=5012*2(x+1)2+2006*4(x+1)+2

回答2:

a=b+1,c=b-1,
2a2+2b2+2c2+2ab+2ac
=a2+2ab+b2+a2+2ac+c2+b2+c2
=(a+b)2+(a+c)2+b2+c2
=(2b+1)2+(2b)2+b2+(b-1)2
=10b2+2b+2
b=2006(x+1)代入即可.