原式=lg(25ⅹ4)+lg[(10/7)x7]
=lg100+lg10
=2+1
=3。
原式=(lg25+lg4)+(lg10/7+lg7)
=lg(25·4)+lg[(10/7)·7]
=lg100+lg10
=lg10²+1
=2lg10+1
=2·1+1
=3
lg25+lg4+lg10/7+lg7
=lg100+lg10
=3lg10
=3
lg25+lg4+lg10/7+lg7
=lg(25x4) + lg[(10/7)x7]
=lg100 +lg10
=2+1
=3
lg25+lg4+lg10/7+lg7
=lg[25*4*(10/7)*7]
=lg1000
=lg(10^3)
=3