Exams › JEE Main › Maths

If one of the lines given by 6x² − xy + 4cy² = 0 is 3x + 4y = 0, then c equals

1. −3
2. 1
3. 3
4. −1

Correct answer: −3

Solution

Write 6x^2 - xy + 4cy^2 = (3x+4y)(2x+qy). Matching gives 4q = 4c so q = c, and the xy-term 3q+8 = -1 -> 3c = -9 -> c = -3.

Related JEE Main Maths questions

• Consider the following statements: Statement 1: The greatest possible number of intersection points formed by 8 circles of the same radius is 56. Statement 2: The greatest possible number of points of intersection obtained when 4 circles of different radii and 4 distinct straight lines are drawn is 50.
• Find the length of the segment from the point (1, 2) to the line x + y + 5 = 0, if the measurement is taken along a line parallel to 3x − y = 7.
• Let p1 and p2 denote the perpendicular distances from the origin to the lines x cos θ + y sin θ = 2a cos 4θ and x sec θ + y cosec θ = 4a cos 2θ, respectively. If mp1² + np2² = 4a², then which of the following is true?
• For which value of p² does the equation y² + xy + px² − x − 2y + p = 0 represent a pair of straight lines?
• An equilateral triangle has one vertex at (2, 3). If the side opposite to this vertex lies on the line x + y = 2, then the equations of the other two sides are
• Which points on the line x + y = 4 are exactly one unit away from the line 4x + 3y = 10?

⚔️ Practice JEE Main Maths free + battle 1v1 →