Q12 of 40 Page 1

The pair of lines represented by the equations 2x + y + 3 = 0 and 4x + ky + 6 = 0 will be parallel if value of k is _________

OR


If the quadratic equation x2 – 2x + k = 0 has equal roots, then value of k is ______


A pair of lines a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 will be parallel if,



So,


⇒ k = 2


OR


Equation x2 – 2x + k = 0 has equal roots.


Discriminant = b2 – 4ac = 0 for equal roots.


⇒ (-2)2 – 4 × (-2) × k = 0


⇒ 4 + 8k = 0



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