Matrix3f A; Vector3f b; A << 1,2,3, 4,5,6, 7,8,9; b << 3, 3, 4; cout << "Here is the matrix A:" << endl << A << endl; cout << "Here is the vector b:" << endl << b << endl; Vector3f x; x = A.lu().solve(b); cout << "The solution is:" << endl << x << endl;