Log по основанию x+1 от (x^2 - 6x - 7) = 1

[latex]\log_{x+1}(x^2-6x-7) = 1 \\ x+1 = x^2-6x-7, x\ \textgreater \ -1 \\ x^2-7x-8 = 0, x\ \textgreater \ -1 \\ x=-1, x=8, x \textgreater -1 \\ x=8[/latex]

....................... ответ 8