По теореме Виета
Проверка:
с)Одз
0\\x>\frac{1}{3}" alt="3x-1>0\\x>\frac{1}{3}" align="absmiddle" class="latex-formula">
d)Одз:
0\\2x+7>0 \end{cases}\\x^2=-4(resh.net)\\x>-3.5\\x>-3.5" alt="\begin{cases} x^2+4>0\\2x+7>0 \end{cases}\\x^2=-4(resh.net)\\x>-3.5\\x>-3.5" align="absmiddle" class="latex-formula">_x\\........(-3.5)//////////////////=>_x\\x\in(-3.5;-1]\cup[3;+\infty)" alt="d)log_{\frac{1}{2}}(x^2+4)\leq\ log_{\frac{1}{2}}(2x+7);\frac{1}{2}<1\\x^2+4\geq2x+7\\x^2-2x-3\geq0\\x_1=3\ ;x_2=-1\\///+///[-1]...-...[3]///+///=>_x\\........(-3.5)//////////////////=>_x\\x\in(-3.5;-1]\cup[3;+\infty)" align="absmiddle" class="latex-formula">