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

Answer:

as given that x=-4 is the root of the given quadratic equation so it will satisfy the equation.

put x=-4 in the given equation.

(-4)²-4k-8=0

16-4k-8=0

4k=8

k=2

Answer 2

if root of this qudratic equation is -4 then it will satisfy this equation hence put -4 at the place of x

so 2

(-4)+k(-4)-8=0

16-4k-8=0

8=4k

k=8/4

k=2