A normal line to a curve passes through a point P on the curve perpendicular to the line tangent to the curve at P (see figure). Use the following equation and graph to determine an equation of the normal line at the given point and illustrate your work by graphing the curve with the normal line.

2 x squared plus xy plus 3 y squared equals 13

(2,1)

-22-44-22-44xy

P(2,1)

Write the equation of the normal line at the given point.

y =