Understanding the Discriminant

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Math › Understanding the Discriminant

Questions 1 - 4

1

Use the discriminant to determine the nature of the roots:

imaginary roots

imaginary root

real roots

real root

Cannot be determined

Explanation

The formula for the discriminant is:

Since the discriminant is negative, there are imaginary roots.

2

Use the discriminant to determine the nature of the roots:

irrational roots

rational roots

imaginary roots

rational root

imaginary root

Explanation

The formula for the discriminant is:

$=1200^{}$

Since the discriminant is positive and not a perfect square, there are irrational roots.

3

Use the discriminant to determine the nature of the roots:

imaginary roots

irrational roots

rational roots

imaginary root

rational root

Explanation

The formula for the discriminant is:

Since the discriminant is negative, there are imaginary roots.

4

Given $2x^{2}+3x-5=0$ , what is the value of the discriminant?

Explanation

In general, the discriminant is $b^{2}-4ac$ .

In this particual case .

Plug in these three values and simplify: $(3)^{2}-4(2)(-5)= 49$

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