[填空题]
A curve is defined b *v)ewe0ouas)rl* t+zye lskq w7:qas8y hs,,9 $x^{2}+10 x y+y^{2}=48$ .
1. Show that $\frac{\mathrm{d} y}{\mathrm{~d} x}=-\frac{2 x+10 y}{10 x+2 y} $.
2. Find the equation of the normal to the curve at the point $ \mathrm{P}(-2,22)$ .y =
3 . Find the distance between the two points on the curve where each tangent is parallel to the line y=-x .
