If one root of the quadratic equation 2×2

+ kx + 4 =0 is -2 then the value of k is

(A)12 (B) 6 (C)-6 (D) -12

2 thoughts on “If one root of the quadratic equation 2×2<br /><br />+ kx + 4 =0 is -2 then the value of k is<br /><br />(A)12 (B) 6 (C)-6 (D) -12”

1. Answer:

   6 is the right answer

   put –2 in the value of x and solve the equation equals to 0

   you’ll get 6

   hope it helps thanks✌

   Reply

2. Given :– If one root of the quadratic equation 2x² + kx + 4 =0 is -2 then the value of k is (A)12 (B) 6 (C)-6 (D) -12

   Answer :–

   we know that, if a is the root of f(x) , then,

   • f(a) = 0 .

   so,

   → f(x) = 2x² + kx + 4

   → f(-2) = 2(-2)² + k(-2) + 4

   → 2 * 4 – 2k + 4 = 0

   → 2k = 8 + 4

   → 2k = 12

   → k = 6 (B) (Ans.)

   Hence, value of k will be 6 .

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