49d^2 - 28d + 4; 4t^2 + 20tr + 25r^2; 16g^2 + 40gs + 25s^2 - 40gs; 49y^2 - 6 + 14y - 49y^2; -9a^2 + 30a - 25.
49d^2 - 28d + 4; 4t^2 + 20tr + 25r^2; 16g^2 + 40gs + 25s^2 - 40gs; 49y^2 - 6 + 14y - 49y^2; -9a^2 + 30a - 25.