Find the Discriminant r^2-r=0

$r^{2} - r = 0$

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

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

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

${(- 1)}^{2} - 4 (1 \cdot 0)$

Evaluate the result to find the discriminant.

Simplify each term.

Raise $- 1$ to the power of $2$ .

$1 - 4 (1 \cdot 0)$

Multiply $0$ by $1$ .

$1 - 4 \cdot 0$

Multiply $- 4$ by $0$ .

$1 + 0$

Add $1$ and $0$ .

$1$