Sove an equation in matrix format

I have an equation:

 X' A X + B' X + C =0      (' -> transpose)
 X' : [ x y]
 A : [ 13 -8 ; -8 1 ]
 B' : [ 59 -43 ]
 C : - 69

This is my decision boundary equation for two features and i need to plot it. Can i do this directly? On solving manually i get an equation: 13 x^2 + y^2 - 16xy + 59x - 43y - 69 But when the number of features increase manually obtaining the equation becomes tedious.

Thank you