Question

高一数学- -，求解啊，郁闷

0.5lg32/49 -4/3lg根号8+lg根号245=？
lg5＾2+2/3lg8+lg5乘lg20+(lg2)＾2=？
（（lg根号2）+lg3-lg根号10）/lg1.8=？
求具体过程 。大哥大姐们 帮帮莪- - 太难了

Answer 1

1.=0.5(lg32-lg49)-4/3lg2^(3/2)+lg[7*5^(1/2)]
=0.5(5lg2-2lg7)-(4/3)*(3/2)lg2+lg7+1/2lg5
=2.5lg2-lg7-2lg2+lg7+0.5lg5
=0.5lg2+0.5lg5
=0.5(lg2+lg5)
=0.5lg10
=0.5
2.=2lg5+2lg2+lg5*lg(5*2^2)+(lg2)^2
=2(lg5+lg2)+lg5*(lg5+2lg2)+(lg2)^2
=2+(lg5)^2+2lg5*lg2+(lg2)^2
=2+(lg5+lg2)^2
=2+1
=3
3.=[lg2^(1/2)+lg3-lg10^(1/2)]/lg(9/5)
=lg[(2^0.5)*3/(10^0.5)]/(lg9-lg5)
=lg[3/(5^0.5)]/[2lg3-2lg5^0.5]
=(lg3-lg5^0.5)/2(lg3-lg5^0.5)
=1/2