Step 1 :Define the Lagrange function as \(L(x, y, \lambda) = 2x^2 + 5y^2 - \lambda(x + y - 7)\).
Step 2 :Find the partial derivatives of L with respect to x, y, and \(\lambda\), and set them equal to zero. This gives us the following equations: \(4x - \lambda = 0\), \(10y - \lambda = 0\), and \(-x - y + 7 = 0\).
Step 3 :Solve the system of equations to find the values of x, y, and \(\lambda\). The solution is \(x = 5\), \(y = 2\), and \(\lambda = 20\).
Step 4 :Substitute these values back into the original equation to verify that they satisfy the constraint \(x + y = 7\).
Step 5 :Final Answer: \(x = \boxed{5}\), \(y = \boxed{2}\)