Question
Question: If equation 4x<sup>2</sup> + 2pxy + 25y<sup>2</sup> + 2x + 5y – 1 = 0 represents parallel lines then...
If equation 4x2 + 2pxy + 25y2 + 2x + 5y – 1 = 0 represents parallel lines then p is equal to:
A
–10
B
10
C
5
D
–2
Explanation
Solution
use h2 = ab & abc + 2fgh – af2 – bg2 – ch2 = 0