lg平方5+lg2*lg5+lg20怎么算?
问题描述：
lg平方5+lg2*lg5+lg20怎么算?
还有 7lg20*(1/2)上面的lg0.7
答
10.把前两项的lg5提出来,得：lg5(lg2+lg5)+lg20=lg10 * lg5 + lg20=lg5+lg20=lg100=10,lg10=1知道吧?好啦,