若x
1满足2x+2
x=5,x
2满足2x+2log
2(x-1)=5,x
1+x
2=______
A.

B.3
C.
【正确答案】
C
【答案解析】 由题意2x
1+2
x1=5,2x
2+2log
2(x
2-1)=5,则2
x1=5-2x
1,x
1=log
2(5-2x
1),即2x
1=2log2(5-2x
1)。令2x
1=7-2t,将其代入上式得7-2t=2log
2(2t-2)=2+2log
2(t-1),则5-2t=2log
2(t-1),故t=x
2,于是2x
1=7-2x
2,
