Q. 155.0( 2 Votes )

If one root the quadratic equation 2x2 + kx – 6 = 0 is 2. Find the value of "k" and also find the other root.

Answer :

Given: One root of 2x2 + kx – 6 = 0 is 2


Then At x = 2, the equation will be satisfied.


2 (2)2 + k × 2 – 6 = 0


8 + 2 k – 6 = 0


2 k + 2 = 0


K = –1


So now the equation becomes 2x2 + 2x – 6 = 0


For this equation, Product of the roots = (–6/2)


Product of roots = – 3


Let a and b be the roots of the equation and it is given that a = 2


2 × b = –3


B = –3/2


Hence the value of k = –1 and other root is –3/2.


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