Use the Limit Definition of the Partial Derivative to Compute $\text { Find } \frac { \partial f } { \partial x } \text { at the point } ( 10 , - 5 ) : f ( x , y ) = 5 x ^ { 2 } + 4 x y + 3 y ^ { 2 }$

Use the limit definition of the partial derivative to compute the indicated partial derivative of the function at the specified point.
- $\text { Find } \frac { \partial f } { \partial x } \text { at the point } ( 10 , - 5 ) : f ( x , y ) = 5 x ^ { 2 } + 4 x y + 3 y ^ { 2 }$