There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ 115{\frac{1}{(0.85X + 115)}}^{2}\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{115}{(0.85X + 115)(0.85X + 115)}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{115}{(0.85X + 115)(0.85X + 115)}\right)}{dx}\\=&\frac{115(\frac{-(0 + 0)}{(0.85X + 115)^{2}})}{(0.85X + 115)} + \frac{115(\frac{-(0 + 0)}{(0.85X + 115)^{2}})}{(0.85X + 115)}\\=&0\\ \end{split}\end{equation} \]

Your problem has not been solved here? Please take a look at the  hot problems ！