lg100-2 lg2=0.3010.... 2/0.3010=.......... 6.6438561897747246957406388589788
lg3=0.47712 lg2=0.***********
是lg(2^x+3)吧 设2^X=K 则2lg(k-1)=lg2 * lg(k+3) lg(k-1)^2=lg(2k+6) k^2-2k+1=2k+6 k=5,-1 又2