Let E be an ellipse whose axes are parallel to the co-ordinates axes, having its center at (3, $$-$$4), one focus at (4, $$-$$4) and one vertex at (5, $$-$$4). If mx $$-$$ y = 4, m > 0 is a tangent to the ellipse E, then the value of 5m² is equal to _____________.

Let L be a common tangent line to the curves

4x² + 9y² = 36 and (2x)² + (2y)² = 31. Then the

square of the slope of the line L is __________.