Question

What is the value of b2 - 4ac for the following equation?

2x 2 - 2x - 1 = 0

Answer 1

`2x^2-2x-1=0`

`\Delta=b^2-4ac`


`\Delta=(-2)^2-4*2*(-1)=4+8=12`

Answer 2

The value of the discriminant is 12.

Explanation:

We are given the quadratic equation is
`2x^2-2x-1=0`.

Now, we know,

The discriminant for the quadratic equation
`ax^2+bx+c=0` is given by
`D=b^2-4ac`.

On comparing the equations, we have,

a= 2, b= -2 and c= -1

So, the discriminant is given by,

`D=(-2)^2-4* 2* (-1)`

i.e.
`D=4+8`

i.e. D= 12

Hence, the value of the discriminant is 12.