1) log 1/9 (13-x)=-2
-log 9 (13-x)=-2 ]*(-1)
log 9 (13-x)=2
2log 3 (13-x)=2 ]:2
log3 (13-x)=1
log3 (13-x)=log3 (3)
13-x=3
x=13-3
x=10
2)log 4(х^2+х)=log 4(х^2+6)
х^2+х=х^2+6
x=6
3)log2(8+3х)=log 2(3+x)+1
log2(8+3х)=log 2(3+x)+log2(2)
log2(8+3х)=log 2(2*(3+x))
8+3x=6+2x
3x-2x=6-8
x=-2