Find the Discriminant -4x^2+9x-1=0

$- 4 x^{2} + 9 x - 1 = 0$

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 $c$ .

$9^{2} - 4 (- 4 \cdot - 1)$

Step 3

Evaluate the result to find the discriminant.

Simplify each term.

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

$81 - 4 (- 4 \cdot - 1)$

Multiply $- 4 (- 4 \cdot - 1)$ .

Multiply $- 4$ by $- 1$ .

$81 - 4 \cdot 4$

Multiply $- 4$ by $4$ .

$81 - 16$

Subtract $16$ from $81$ .

$65$