1.(lg2)^3+(lg5)^3+3lg2*lg5=2.若lg(x-y)+lg(x+2y)=lg2+lgx+lgy,则x/y=
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1.(lg2)^3+(lg5)^3+3lg2*lg5=2.若lg(x-y)+lg(x+2y)=lg2+lgx+lgy,则x/y=
1.(lg2)^3+(lg5)^3+3lg2*lg5=
2.若lg(x-y)+lg(x+2y)=lg2+lgx+lgy,则x/y=
1.(lg2)^3+(lg5)^3+3lg2*lg5=2.若lg(x-y)+lg(x+2y)=lg2+lgx+lgy,则x/y=
1.设x=lg2,y=lg5,则x+y=lg2+lg5=lg10=1
原式=x^3+y^3+3xy
=(x+y)(x^2-xy+y^2)+3xy
=x^2-xy+y^2+3xy
=x^2+2xy+y^2
=(x+y)^2
=1
2.
lg(x-y)+lg(x+2y)=lg2+lgx+lgy
lg(x-y)(x+2y)=lg2xy
(x-y)(x+2y)=2xy
x^2+xy-2y^2=2xy
x^2-xy-2y^2=0
设x/y=k
k^2y^2-ky^2-2y^2=0
(k^2-k-2)Y^2=0
k^2-k-2=0
(k+1)(k-2)=0
k=-1,k=2
x/y=-1(舍),x/y=2
lg2(lg5-lg2)-lg5(lg5+3lg2)等于
(lg2)^3+(lg5)^3+3lg2*lg5等于?
(lg2)^3+(lg5)^3+3*lg2*lg5
(lg2)³+(lg5)³+3lg2×lg5
3+lg5+(lg2)^2
3lg2-lg5=
对数lg2*lg5=?2lg(5)+2/3 lg8+lg5*lg20+lg2 =lg5^2+lg8^(2/3)+lg5*(lg4+lg5)+lg2 =lg100+lg5+2lg2*lg5+lg2 =2+(lg5+lg2) =2+1 =3 第二个等号lg5*(lg4+lg5)为什么=lg5+2lg2*lg5
(lg2)^3+(lg5)^3+3lg2lg5怎么算=(lg5+lg2)[(lg5)²-lg5lg2+(lg2)²]+3lg5lg2为什么
3lg5*lg2+(3lg2)^2=?
(lg2)^3+(lg5)^3+3lg2*lg5怎么算RT
(lg2)^3+3lg2·lg5+(lg5)^3 怎么算?
(lg2)^3+(lg5)^3+3lg2*lg5 这些怎么算.
(lg2)^3+3lg2·lg5+(lg5)^3 怎么算?
(lg2)^3+(lg5)^3+3lg2*lg5的值为?
(lg2)^3+3lg2乘lg5+(lg5)^3
求解3lg5+3lg2*lg5+3lg2^2~
(lg2)³+(lg5)³+3lg2×lg5(等于多少?)
(lg2)³+(lg5)³+3lg2×lg5(怎么算呀,