Question

Which of the following is the value of k, if one root
of the quadratic equation x²+ Kx- 8=0 is -4?​

Answer 1

$\huge\tt{\bold{\underline{\underline{Question᎓}}}}$

Which of the following is the value of k, if one root

of the quadratic equation x²+ Kx- 8=0 is -4?

$\huge\tt{\bold{\underline{\underline{Answer᎓}}}}$

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Given that one of the root is -4

put -4 in the given equation:-

$= > {x}^{2} + kx - 8 = 0$

$= > {( - 4)}^{2} + k( - 4) - 8 = 0$

$= > 16 - 4k - 8 = 0$

$= > 8 - 4k = 0$

$= > - 4k = - 8$

$\bold{\red{ = > k = 2}}$

Now let's check whether k's value satisfies the equation or not-

$= > {x}^{2} + kx - 8 = 0$

$= > {( - 4)}^{2} + (2) ( - 4) - 8 = 0$

$= > 16 - 8 - 8 = 0$

$= > 16 - 16 = 0$

Hence,the value of k is 2

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