1.lg²5+lg2×lg5+lg2 2.(lg2)³ +(lg 5)³ +3lg 2×l
1个回答

1.lg²5+lg2×lg5+lg2

=lg5(lg5+lg2)+lg2

=lg5*lg(5*2)+lg2

=lg5+lg2

=1

2.(lg2)³ +(lg 5)³ +3lg 2×lg 5

=(lg2+lg5)(lg²2-lg2*lg5+lg²5)+3lg 2×lg 5

=lg²2+2lg2*lg5+lg²5

=(lg2+lg5)²

=1

3.7 的lg20次方×(1/2)的lg0.7次方

=7 的(lg2*10)次方×(1/2)的(lg7*0.1)次方

=7 ^(1+lg2)×(1/2)^(-1+lg7)

=7*2*7^lg2*(1/2)^lg7

=14*7^lg2/2^lg7

4.lg500+lg8/5-1/2lg64+50(lg2+lg5)²

=lg500+lg8/5-lg8+50

=lg(500*8/5/8)+50

=lg100+50

=52