lg(4的x次+2)=lg2的x次+lg3
lg(4^x+2)=lg(2^x*3)
所以,4^x+2=3*2^x
(2^x)^2-3*2^x+2=0
(2^x-1)(2^x-2)=0
2^x-1=0
x=0
2^x-2=0
x=1