0} \atop {6x+7=7^{4}}} \right. " alt=" \left \{ {{6x+7>0} \atop {6x+7=7^{4}}} \right. " align="absmiddle" class="latex-formula">
-\frac{7}{6} } \atop {6x=7^{4}-7}} \right. " alt=" \left \{ {{x>-\frac{7}{6} } \atop {6x=7^{4}-7}} \right. " align="absmiddle" class="latex-formula">
-\frac{7}{6} } \atop {x=\frac{7}{6}*(7^{3}-1)}} \right. " alt=" \left \{ {{x>-\frac{7}{6} } \atop {x=\frac{7}{6}*(7^{3}-1)}} \right. " align="absmiddle" class="latex-formula">
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ответ
Проверка:
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верно
Ответ: x=399