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,

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

$\text {For a quadratic equation } a x^{2}+b x+c=0, \text { where } a \neq 0$

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