1+log2真数（2lga—x）除以log2真数x=2logx真数2logx(x)+log2[(2lga-x)]/log2(x)=logx(4)logx(x)+logx(2lga-x)=logx(4)logx[x(2lga-x)]=logx(4)x(2lga-x)=4x²-2lga*x+4=0用求根公式解得x=[2lga±根号(4(lga)&su...