Question

If one of the roots of the quadratic equation kx²+2x-8=0 is -2 then what is the value of k

Answer 1

Answer:

Step-by-step explanation:see the picture below

Answer 2

Given,

The quadratic equation kx²+2x-8=0 is given along with one root of this equation is -2.

To find,

The value of k.

Solution,

The value of k for the quadratic equation kx²+2x-8=0 whose one root is -2 is 3.

We can simply find the value of k by substituting the given zero of the equation in the given quadratic equation.

p(x) = kx²+2x-8

Substituting the zero of the equation in the quadratic equation, we get

p(-2) = k(-2)² +2(-2) -8

        = 4k -4-8

        = 4k-12

According to the given condition,

        4k-12 =0

              4k = 12

                k = 3

Hence, the value of k for the quadratic equation kx²+2x-8=0 whose one root is -2 is 3.