If one root of the equation 3x*x - kx - 2=0 is 2, find the value of k. Also find the other root.

Asked by Samiksha Srivastava | 16th Jan, 2014, 05:40: PM

Expert Answer:

Given, one root of the equation 3x2 - kx - 2=0 is 2.
So, we have:
3(2)2 - k(2) - 2=0
12 - 2k - 2 = 0
10 = 2k
k = 5
 
Now, the quadratic equation becomes:
3x2 - 5x - 2=0
3x2 - 6x + x - 2=0
3x(x - 2) + 1(x - 2) = 0
(x - 2)(3x + 1) = 0
x = 2, -1/3
 
Thus, the other root is -1/3.

Answered by  | 16th Jan, 2014, 06:21: PM

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