log2^(x-1)=log4^x
则 log2^(x-1)=log4^(x-1)²=log4^x
则（x-1）²=x
所以x²-3x+1=0
则x=（3士√5）/2log2^(x-1)=log4^(x-1)²这一步不太明白请教loga b=l oga² b²