(2/3)lg(8)=(2/3)lg(2³)=2lg2
则：
原式=[lg5]²＋2lg2＋lg5×[lg2＋lg10]
.=[lg5]²＋2lg2＋lg5×[1＋lg2]
.=[lg5]²＋2lg2＋lg5＋lg2×lg5
.=lg5[lg2＋lg5]＋2lg2＋lg5
.=lg5＋2lg2＋lg5
.=2lg5＋2lg2
.=2[lg2＋lg5]
.=2