0\; \; \Rightarrow \; \; (6^{x}-12)>-12\\\\y\in (-12;+\infty ) " alt=" a)\; \; y=6x-12\\\\x\in (-\infty ,+\infty )\; \; \Rightarrow y=6x-12\in (-\infty ,+\infty )\\\\\\b)\; \; y=6^{x}-12\\\\6^{x}>0\; \; \Rightarrow \; \; (6^{x}-12)>-12\\\\y\in (-12;+\infty ) " align="absmiddle" class="latex-formula">