Question

Joint equation of pair of lines which passes through origin and are perpendicular to the lines represented the equation:

y² + 3xy – 6x + 5y – 14 = 0, will be-

• A. y² – 3xy = 0
• B. 3y² – xy = 0
• C. x² – 3xy = 0
• D. 3x² – xy = 0

Answer 1

Answer: (C)

x² – 3xy = 0

Answer 2

Homogeneous part of the given equation is

y² + 3xy = 0, which represents straight lines

y = 0 and y + 3x

= 0. Now lines perpendicular to these lines are

x = 0 & x – 3y = 0

So combined equation of above lines is x² – 3xy = 0.