Question

log4^(13-3x)*log(x-1)^2=1的解

Answer 1

log4^(13-3x)*log(x-1)^2=1
log4^(13-3x)=1/log(x-1)^2
1/2*log2^(13-3x)=log2^(x-1)
所以枣蚂√凳搏埋(13-3x)=x-1
平方
13-3x=x^2-2x+1
x^2+x-12=0
x=-4,x=3
真数13-3x>0,x-1>银兄0
所以x=3

Answer 2

a5+a6
=(a1+a2+a3+a4+a5+a6)-(a1+a2+a3+a4)
=S6-S4
=7/敏渗即a=2b
所以a2=4b2
ab=2b2
所以分子=4b2-2b2-b2=b2
分母=4b2+b2=5b2
所以缺坦=5分之1
选？
题错了桥扮脊
0
8-5/6
=1/24