(3lg2+3)lg5+3(lg2)平方-3lg10
=3lg2*lg5+3lg5+3(lg2)^2-3
=3lg2(lg5+lg2)+3lg5-3
=3lg2+3lg5-3
=3(lg2+lg5)-3
=3-3
=0 注意:lg2+lg5=lg10=1
(3lg2+3)lg5+3(lg2)平方-3lg10
=3lg2*lg5+3lg5+3(lg2)^2-3
=3lg2(lg5+lg2)+3lg5-3
=3lg2+3lg5-3
=3(lg2+lg5)-3
=3-3
=0 注意:lg2+lg5=lg10=1