1 answer
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#1 ambiguous
#2 log(x(x-1)) = log 6
x(x-1) = 6
x = 3
#3 assuming base 4 throughout,
log25-logx+log3-log7 = 1/2
log(75/7x) = 1/2
75/7x = 4^(1/2) = 2
14x = 75
x = 75/14
Unusual answer. I suspect a typo.