There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ x(20 - 2x)(40 - 2x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = 4x^{3} - 120x^{2} + 800x\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( 4x^{3} - 120x^{2} + 800x\right)}{dx}\\=&4*3x^{2} - 120*2x + 800\\=&12x^{2} - 240x + 800\\ \end{split}\end{equation} \]

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