Solve logarithm equation: log2 (12b - 21) - log2 (b^2 - 3)=2

Hn, well you should use the rule to answer this.. 
Sorry if this doesn't seem to help, but here is the explanation: 









Hn, so from this information we can determine that this solution does not work. And so forth your solution set shall indeed be: {x= 0}

I wish you good luck on your homework and hopefully I was somewhat beneficial to your needs. 

Best regards~ Sans

Idon’t understand sorry