0\\O.D.3.:\;x-3>0\Rightarrow x>3\\\log_{\frac13}(x-3)>0\\x-3>\left(\frac13\right)^0\\x-3>1\\x>4\\2.\;\log_8(4-2x)\geq2\\O.D.3.:\;4-2x>0\Rightarrow x<2\\\log_8(4-2x)\geq2\\4-2x\geq8^2\\-2x\geq60\\x\leq-30" alt="1.\;\log_{\frac13}(x-3)>0\\O.D.3.:\;x-3>0\Rightarrow x>3\\\log_{\frac13}(x-3)>0\\x-3>\left(\frac13\right)^0\\x-3>1\\x>4\\2.\;\log_8(4-2x)\geq2\\O.D.3.:\;4-2x>0\Rightarrow x<2\\\log_8(4-2x)\geq2\\4-2x\geq8^2\\-2x\geq60\\x\leq-30" align="absmiddle" class="latex-formula">