Determine the Nature of the Roots Using the Discriminant -2x^2+x-28=0

$- 2 x^{2} + x - 28 = 0$

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 $c$ .

$1^{2} - 4 (- 2 \cdot - 28)$

Step 3

Evaluate the result to find the discriminant.

Simplify each term.

One to any power is one.

$1 - 4 (- 2 \cdot - 28)$

Multiply $- 4 (- 2 \cdot - 28)$ .

Multiply $- 2$ by $- 28$ .

$1 - 4 \cdot 56$

Multiply $- 4$ by $56$ .

$1 - 224$

Subtract $224$ from $1$ .

$- 223$

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