There are 1 questions in this calculation: for each question, the 1 derivative of y is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ (83x - 2{x}^{2} - xy) + (51y - xy - {6}^{2}) - (3x + y)\ with\ respect\ to\ y：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = - 2xy + 80x + 50y - 2x^{2} - 36\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( - 2xy + 80x + 50y - 2x^{2} - 36\right)}{dy}\\=& - 2x + 0 + 50 + 0 + 0\\=& - 2x + 50\\ \end{split}\end{equation} \]

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