Question

Find the discriminant of the following equation:

f(x) = 4x² + 6x -5
1) 116
2) -68
3) 92
4) -44

Answer 1

Option 1

The discriminant of given equation is 116

Solution:

We have to find the discriminant of given equation

Given equation is:

`f(x) = 4x^2+6x-5`

To find discriminant,

`4x^2+6x-5 = 0`

`\text {For a quadratic equation } a x^(2)+b x+c=0, \text { where } a \\eq 0`

Discriminant is given by:

`D = b^2-4ac`

On comparing the given quadratic equation
`4x^2+6x-5 = 0` with general quadratic equation
`ax^2+bx+c = 0`

a = 4

b = 6

c = -5

Substituting in above formula,

`D = 6^2-4(4)(-5)\\\\D = 36-16(-5)\\\\D = 36+80\\\\D = 116`

Thus discriminant of given equation is 116