Find the Discriminant -8x^2+9x-4=0

$- 8 x^{2} + 9 x - 4 = 0$

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 $c$ .

$9^{2} - 4 (- 8 \cdot - 4)$

Step 3

Evaluate the result to find the discriminant.

Simplify each term.

Raise $9$ to the power of $2$ .

$81 - 4 (- 8 \cdot - 4)$

Multiply $- 4 (- 8 \cdot - 4)$ .

Multiply $- 8$ by $- 4$ .

$81 - 4 \cdot 32$

Multiply $- 4$ by $32$ .

$81 - 128$

Subtract $128$ from $81$ .

$- 47$