早教吧 育儿知识 作业答案 考试题库 百科 知识分享

解-log2^[9^(x-1)-5]=-log2^[3^(x-1)]-2

题目详情
解-log2^[9^(x-1)-5]=-log2^[3^(x-1)]-2
▼优质解答
答案和解析
-log2^[9^(x-1)-5]=-log2^[3^(x-1)]-2
-log2^[9^(x-1)-5]=-log2^[3^(x-1)]-log2^4
-log2^[9^(x-1)-5]=-(log2^[3^(x-1)]+log2^4)
-log2^[9^(x-1)-5]=-log2^[3^(x-1)]*4
log2^[9^(x-1)-5]=log2^[3^(x-1)]*4
[9^(x-1)-5]=[3^(x-1)]*4
[3^(x-1)]^2-4*3^(x-1)-5=0
[3^(x-1)-5][3^(x-1)+1]=0
3^(x-1)=5或3^(x-1)=-1
3^(x-1)=-1无解
3^(x-1)=5
x-1=log3^5
x=log3^5+1=log3^15