Ellipse 3x2+4y2=1: a2=31, b2=41, e=21.
Tangent at (x0,y0): 3x0x+4y0y=1.
Comparing with αx+4y=7:
4y0=74⇒y0=71 and 3x0=7α.
Substituting in ellipse equation: 21α2+74=1⇒α2=9⇒α=3.
P=(71,71).
Focal distances =a±ex0=31±271.
One focal distance is 31+271.