For the function $z=3x^3-9y^{2}7xy,$ find $\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{x}},\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{y}},\frac{\text{d}\text{e}\text{l}}{\text{d}\text{e}\text{l}\text{x}}z(-1,-5),$ and $\frac{\text{d}\text{e}\text{l}}{\text{d}\text{e}\text{l}\text{y}}z(-1,-5).$

$\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{x}}=$

$\frac{\text{d}\text{e}\text{l}\text{z}}{\text{d}\text{e}\text{l}\text{y}}=$

$\frac{\text{d}\text{e}\text{l}}{\text{d}\text{e}\text{l}\text{x}}z(-1,-5)=$

$($Simplify your answer.$)$

$\frac{\text{d}\text{e}\text{l}}{\text{d}\text{e}\text{l}\text{y}}z(-1,-5)=$

$($Simplify your answer.$)$