There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ (50 - x)(4000 + 200x) - 400(50 - x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = 6400x - 200x^{2} + 180000\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( 6400x - 200x^{2} + 180000\right)}{dx}\\=&6400 - 200*2x + 0\\=& - 400x + 6400\\ \end{split}\end{equation} \]

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