Consider the problem of minimizing (x, y) = x 2 + 2x + 9y 2 + 4y

Consider the problem of minimizing ƒ(x, y) = x² + 2x + 9y² + 4y + 8xy subject to x + y = 1.

(a) Find the solution using the method of Lagrange multipliers.

(b) Suppose you erroneously applied the method of finding the discriminant D from the previous section to determine whether the point found in part (a) is a minimum. What does the test erroneously tell you about the point?