Question

If one root of the quadratic equation 2x2 + 2x + k = 0 is , then find the
value of k.​

Answer 1

Given :

The quadratic equation is 2 x² + 2 x + k = 0

One of the root of equation = - $\dfrac{1}{3}$

To Find :

The value of k

Solution :

quadratic equation is 2 x² + 2 x + k = 0

As one of its root = - $\dfrac{1}{3}$

So, This root must satisfy the given equation

So, put x =  - $\dfrac{1}{3}$ in the given equation

∴ 2 (  - $\dfrac{1}{3}$) ² + 2 (  - $\dfrac{1}{3}$ )+ k = 0

Or,  2 × $\dfrac{1}{9}$ - 2 ×  $\dfrac{1}{3}$  + k = 0

Or,  $\dfrac{2}{9}$ - $\dfrac{2}{3}$ + k = 0

Take L.C.M

i.e    $\dfrac{2-6}{9}$ + k = 0

Or,  $\dfrac{-4}{9}$ + k = 0

∴        k = $\dfrac{4}{9}$

Hence, The value of k is  $\dfrac{4}{9}$    . Answer

Answer 2

Answer:

4/9

Step-by-step explanation:

d=9A^2-36

A=PLUS MINUS 2

So put the values and you will get ur answer thank you