Question

the curve x^2+4y^2=7+3xy a. show that there is a point p with the x coordinate 3 at which the line tangent to the curve at p is horizontal. find the y-coordinate of p. b. find the value of d^2y/dx^2 at the point p found in a. Does the curve have a local min, max, or neither at point p.
i need help with the second part please