MHT CET 2017 Math Solved Paper

(a) We have, pair of line is px2−qy2 = 0 ...(i)
After comparing eq. (i) with ax2+2hxy+by2 = 0,
we get a = p, b = -q, h = 0
As slopes of pair of lines represented by
ax2+2hxy+by2 = 0
are real and distinct iff h2−ab > 0
So, 0 + p q > 0
Hence, pq > 0