15) \((x-7)^2 = \sqrt{11}(x-7)\)
\((x-7)^2 - \sqrt{11}(x-7) = 0\)
\((x-7)(x-7 - \sqrt{11}) = 0\)
\(x-7 = 0\) или \(x-7 - \sqrt{11} = 0\)
\(x = 7\) или \(x = 7 + \sqrt{11}\)
Ответ: \(x = 7; x = 7 + \sqrt{11}\)