There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ (83x - 2{x}^{2} - xy) + (51y - xy - {y}^{2}) - (3x + y)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = 80x - 2x^{2} - 2yx + 50y - y^{2}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( 80x - 2x^{2} - 2yx + 50y - y^{2}\right)}{dx}\\=&80 - 2*2x - 2y + 0 + 0\\=& - 4x - 2y + 80\\ \end{split}\end{equation} \]

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