解方程 $\ln(x-5)=7-\ln x$。答案保留 $2$ 位小数。

Answer all questions. You should use a calculator where appropriate.

You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.

Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.

请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程；仅给出计算器答案而没有过程，不予评分。除非题目另有精度要求，非精确数值答案保留 3 位有效数字，以度为单位的角度保留 1 位小数。

先合并对数再指数化，得到二次方程。原对数要求 $x>5$，因此只保留一个根。

The domain is $x>5$. Rearranging,

Thus

Solving,

The negative root is outside the domain. Hence

to 2 decimal places.