(x+y)xy/(x-y)xy=120/30
(x+y)/(x-y)=4
x+y=4x-4y
3x=5y,x=5y/3
(5y/3-y)(5yˇ2/3)=30
2y/3.(5yˇ2/3)=30, 10/9yˇ3=30,yˇ3=27,y=3
x=5y/3=5
/x,y/=/5,3/
1
log(2)m+log(2)n=9+5=14
2
log(3)m-log(3)9-log(3)n=13-2-7=4
3
3/5*log(5)b=0,6*(-2)=-1,2
4
-1/4*log(9)m=-1/4*(-4)=1
5
25^(1/2log(81)5)=25^1/log(81)25)=25^log(25)81=81
6
1/4*(1/2)^log(1/2)14=1/4*14=3,5