Question

What is the discriminant of the polynomial below?

2х2 + 4x - 9
А. 88
в. 22
с. -56
D. -2

Answer 1

Let d = discriminant

d = b^2 - 4ac

Let a = 2, b = 4 and c = -9

We now plug and chug.

d = (4)^2 - 4(2)(-9)

d = 16 - 8(-9)

d = 16 + 72

d = 88

Answer 2

А. 88

Explanation:

2х^2 + 4x - 9

This is in the form

ax^2 +bx +c

where a=2 b=4 and c=-9

The discriminant is

b^2 -4ac

Substituting into the equation

4^2 -4(2) (-9)

16 - (-72)

16+72

88