Find the matrix A of the quadratic form associated with the equation. 3x² - 8xy − 3y² + 15 = 0 Find the eigenvalues of A. (Enter your answers as a comma-separated list.) λ = Find an orthogonal matrix P such that PTAP is diagonal. (Enter the matrix in the form [[row 1], [row 2], ...], where each row is a comma-separated list.) P =