There are 1 questions in this calculation: for each question, the 1 derivative of y is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ -0.25(x + y + 1)(x + 1)(y - 1)\ with\ respect\ to\ y：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = -0.25x^{2}y - 0.25xy - 0.25xy^{2} + 0.25xy - 0.25xy + 0.25x - 0.25y^{2} + 0.25y + 0.25x^{2} + 0.25x - 0.25y + 0.25\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( -0.25x^{2}y - 0.25xy - 0.25xy^{2} + 0.25xy - 0.25xy + 0.25x - 0.25y^{2} + 0.25y + 0.25x^{2} + 0.25x - 0.25y + 0.25\right)}{dy}\\=&-0.25x^{2} - 0.25x - 0.25x*2y + 0.25x - 0.25x + 0 - 0.25*2y + 0.25 + 0 + 0 - 0.25 + 0\\=& - 0.5xy - 0.25x - 0.25x^{2} + 0.25x - 0.25x - 0.5y\\ \end{split}\end{equation} \]

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