10.
1) log₂3 + log₂5 = log₂(3*5) = log₂15
2log₂4 = log₂4²=log₂16
log₂15 < log₂16 (log₂3 + log₂5)<2log₂4<br>
2) lg12-lg5 = lg(12:5)=lg(2,4)
lg5 - lg2 = lg(5:2) = lg(2,5)
lg 2,4 < lg 2,5 (lg12 - lg5) < (lg 5 - lg 2)
11. 3)
Должно быть 
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