Question

If x = 3 is one root of the quadratic equation x2 – 2kx – 6 = 0, then find the value of k.

Answer 1

x²-2kx-6=0

put x=3, in the poly.n eqn

3²-2k×3-6=0

9-6k-6=0

6k=3

k=1/2

Answer 2

x = 3

x² - 2kx - 6 = 0

Put the value of x the equation.

x² - 2kx - 6 = 0

( 3 ) ² - 2(k) ( 3 ) - 6 = 0

9 - 6k - 6 = 0

- 6k + 9 - 6 = 0

- 6k + 3 = 0

- 6k = - 3

6k = 3

k = 3 / 6

k = 1 / 2

I hope it help you...

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