(2)log_ab=.

(1)a(a、b是不为1的正数，c>0)；

(2)lg5·lg8000+(lg2)²－lg6+lg0.06；

(3)5·()；

(4)(log₂125+log₄25+log₈5)·(log₁₂₅8+log₂₅4+log₅2).

(1)求lg72,lg4.5；

(2)若lgx=－1.2219,求x.

(2)(lg5)²+lg2·lg50；

(3)2log₃2－log₃+log₃8－5.

①lg(x－3)²＜2与lg(x－3)＜1；②lgx+lg(2－x)＞0与lg(2x－x²)＞0；③log₂(x+3)－log₂x＞1与

log₂(x+3)＞log₂(2x).

其中两不等式同解的组的序号为________.

①log_ax²=2log_ax  ②log_ax²=2log_a|x|  ③log_a(xy)=log_ax+log_ay  ④log_a(xy)=log_a|x|+log_a|y|

A.②④                                                            B.①③

C.①④                                                            D.②③

A.220                                                         B.8       

C.22                                                           D.14

①lg=－2  ②log₃3=  ③2=5  ④e^lne=1  ⑤3^lg3=3  ⑥5^ln5=5

A.①②③                                                               B.①②③④

C.①②③④⑤                                                        D.①②③④⑤⑥