![image](https://tex.z-dn.net/?f=log_%7B%5Cfrac%7B1%7D%7B7%7D%7D%284x%2B1%29%3C-2%7C4x%2B1%3E0%2C+4x%3E-1%2C+x%3E-%5Cfrac%7B1%7D%7B4%7D%5C%5C%5C%5Clog_%7B%5Cfrac%7B1%7D%7B7%7D%7D%284x%2B1%29%3Clog_%7B%5Cfrac%7B1%7D%7B7%7D%7D49%5C%5C%5C%5C4x%2B1%3E49%5C%5C%5C%5C4x%3E48%7C%3A4%5C%5C%5C%5Cx%3E12%5C%5C%5C%5Cx+%5Cin+%2812%3B%2B%5Cinfty%29)
0, 4x>-1, x>-\frac{1}{4}\\\\log_{\frac{1}{7}}(4x+1)49\\\\4x>48|:4\\\\x>12\\\\x \in (12;+\infty)" alt="log_{\frac{1}{7}}(4x+1)<-2|4x+1>0, 4x>-1, x>-\frac{1}{4}\\\\log_{\frac{1}{7}}(4x+1)49\\\\4x>48|:4\\\\x>12\\\\x \in (12;+\infty)" align="absmiddle" class="latex-formula">