A circle passing through the point $$P(\alpha, \beta)$$ in the first quadrant touches the two coordinate axes at the points $$A$$ and $$B$$. The point $$P$$ is above the line $$A B$$. The point $$Q$$ on the line segment $$A B$$ is the foot of perpendicular from $$P$$ on $$A B$$. If $$P Q$$ is equal to 11 units, then the value of $$\alpha \beta$$ is ___________.

The coefficient of $$x^{18}$$ in the expansion of $$\left(x^{4}-\frac{1}{x^{3}}\right)^{15}$$ is __________.

Let the image of the point $$\mathrm{P}(1,2,3)$$ in the plane $$2 x-y+z=9$$ be $$\mathrm{Q}$$. If the coordinates of the point $$\mathrm{R}$$ are $$(6,10,7)$$, then the square of the area of the triangle $$\mathrm{PQR}$$ is _____________.

The number of ways of giving 20 distinct oranges to 3 children such that each child gets at least one orange is ___________.