lg25+23lg8+lg5*lg20+(lg2)²
=lg25+lg4+lg5*lg4*5+(lg2)²
=lg100+lg5*(lg4+lg5)+(lg2)²
=2+2*lg5*lg2+(lg5)²+(lg2)²
=2+(lg5+lg2)²
=2+1
=3
lg25+23lg8+lg5*lg20+(lg2)²
=lg25+lg4+lg5*lg4*5+(lg2)²
=lg100+lg5*(lg4+lg5)+(lg2)²
=2+2*lg5*lg2+(lg5)²+(lg2)²
=2+(lg5+lg2)²
=2+1
=3