Q1 of 134 Page 4

If one root of the quadratic equation 2x2+kx-6=0 is 2, find the value of k. Also find the other root.

Given: quadratic equation 2x2+kx-6=0

One root = 2


To find: The value of another root.


Formula used: If “p” is root of quadratic equation ax2+bx+c=0


Then a(p)2+b(p)+c=0


Explanation:


Since x=2 is the root of the equation 2x2+kx-6=0,


⇒ 2(2)2+k (2)-6=0


⇒ 2(4) +2k-6=0


⇒ 8 +2k-6=0


⇒ 2+2k=0


⇒ 2 = -2k


⇒ k = -1


Now put the value of k in the equation to get,


2x2+(-1) x-6=0


⇒ 2x2-x-6=0


⇒ 2x2-4x+3x-6=0


⇒ 2x(x-2) +3(x-2) =0


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