Question

If -4 is one root of the equation
$x {}^{2} + kx - 8$
is equal to zero then find the value of k
A)1 b)2 c)4 d)0 or 4​

Answer 1

$\huge{\mathcal{\blue{\underline{Answer}}}}$

$x {}^{2} + kx - 8 = 0 \\ ( - 4) {}^{2} + k( - 4) - 8 = 0 \\ 16 - 4k - 8 = 0 \\ 8 - 4k = 0 \\ - 4k = - 8 \\ k = \frac{ - 8}{ - 4}$

$\huge{\mathcal{\blue{\underline{k=2}}}}$