Finite Math Examples

$2 x^{2} + x + 5 = 0$

Step 1

The discriminant of a quadratic is the expression inside the radical of the quadratic formula.

$b^{2} - 4 (a c)$

Step 2

Substitute in the values of $a$ , $b$ , and $c$ .

$1^{2} - 4 (2 \cdot 5)$

Step 3

Evaluate the result to find the discriminant.

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Step 3.1

Simplify each term.

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Step 3.1.1

One to any power is one.

$1 - 4 (2 \cdot 5)$

Step 3.1.2

Multiply $- 4 (2 \cdot 5)$ .

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Step 3.1.2.1

Multiply $2$ by $5$ .

$1 - 4 \cdot 10$

Step 3.1.2.2

Multiply $- 4$ by $10$ .

$1 - 40$

Step 3.2

Subtract $40$ from $1$ .

$- 39$

Step 4

The nature of the roots of the quadratic can fall into one of three categories depending on the value of the discriminant $(Δ)$ :

$Δ > 0$ means there are $2$ distinct real roots.

$Δ = 0$ means there are $2$ equal real roots, or $1$ distinct real root.

$Δ < 0$ means there are no real roots, but $2$ complex roots.

Since the discriminant is less than $0$ there are no real roots. Instead, there are two complex roots.

Two Complex Roots