The correct options are
B 2p−3q=0
C (p−1)(q−1)=2
The general equation of second degree is :
ax2+2hxy+by2+2gx+2fy+c=0
Given : px2+(2−q)xy+3y2−6qx+30y+6q=0
Comparing both,
a=p, b=3, h=2−q2,f=15, g=3q, c=6q
For circle, coefficient of xy=0
and coefficient of x2= coefficient of y2
⇒2−q=0⇒q=2
and p=3
Now, Δ=abc+2fgh−af2−bg2−ch2
=18pq+2(15)(3q)(2−q2)−p(15)2−3(3q)2−6q(2−q2)2
=−675
⇒Δ≠0