Помогите решить Логарифмы !!!!!!!!

9
log(3)4=log(5)4/log(5)3
ln25=log(5)25/log(5)e=2/log(5)e
10
lnx=ln4+2/3*ln2_ln(a+b)-ln7-2lnb
11
log(c)x=log(c)81+1/2log(c)(a/b)-log(c)c²=log(c)[81/c²*√(a/b)]
x=81/c²*√(a/b)
12
{x²-4≠0⇒x²≠4⇒x≠2 U x≠-2
{x²+x-12<0⇒-4<x<3
x1+x2=-1 U x1*x2=-12⇒x1=-4 U x2=3
x∈(-4;-2) U (-2;2) U (2;3)