On the circle x2+y2+4x+8y−38=0 ∵2g=4 ⇒g=2 2f=8 ⇒f=4 Centre =(−g,−f) Whose centre is C(−2−4) Let PB be a diameter. Then, C in mid-point of PE and Let‌B(x,y). Then, (−2,−4)=(
−9+x
2
,
−1+y
2
) ⇒
−9+x
2
=−2 and
−1+y
2
=−4 ⇒x=5 and y=−7 ∴B(5,−7) Tangent at (5,−7) 5x−7y+2(x+5)+4(y−7)−38=0 5x−7y+2x+10+4y−28−38=0 ⇒7x−3y=56