Question

find the value of k for which x=-2 is a root of the quadratic kx2+x-6=0
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Answer 1

Answer:

k = 2

Step-by-step explanation:

$x = - 2\: is \: given\\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: k {x}^{2}+x - 6 = 0 \\ {-2}^{2} \times k + ( - 2) - 6 = 0 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: 4k - 2 - 6 = 0 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: 4k - 8 = 0 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: 4k = 8 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: k = \frac{8}{4} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: hence \: k = 2$

Answer 2

Answer:

k = 2

Step-by-step explanation:

x = -2

kx^2 + x - 6 = 0

k(-2)^2 +(-2)-6 = 0

k × 4 - 2 - 6 = 0

4k - 2 - 6 = 0

4k = 0 + 6 + 2

4k = 8

k = 8 / 4

k = 2 / 1

k = 2

Hope you will be happy getting this answer :)