Solve Using the Quadratic Formula 81-m^2=0

$81 - m^{2} = 0$

Step 1

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 2

Substitute the values $a = - 1$ , $b = 0$ , and $c = 81$ into the quadratic formula and solve for $m$ .

$\frac{0 \pm \sqrt{0^{2} - 4 \cdot (- 1 \cdot 81)}}{2 \cdot - 1}$

Step 3

Simplify.

Simplify the numerator.

Raising $0$ to any positive power yields $0$ .

$m = \frac{0 \pm \sqrt{0 - 4 \cdot - 1 \cdot 81}}{2 \cdot - 1}$

Multiply $- 4 \cdot - 1 \cdot 81$ .

Multiply $- 4$ by $- 1$ .

$m = \frac{0 \pm \sqrt{0 + 4 \cdot 81}}{2 \cdot - 1}$

Multiply $4$ by $81$ .

$m = \frac{0 \pm \sqrt{0 + 324}}{2 \cdot - 1}$

Add $0$ and $324$ .

$m = \frac{0 \pm \sqrt{324}}{2 \cdot - 1}$

Rewrite $324$ as $18^{2}$ .

$m = \frac{0 \pm \sqrt{18^{2}}}{2 \cdot - 1}$

Pull terms out from under the radical, assuming positive real numbers.

$m = \frac{0 \pm 18}{2 \cdot - 1}$

Multiply $2$ by $- 1$ .

$m = \frac{0 \pm 18}{- 2}$

Simplify $\frac{0 \pm 18}{- 2}$ .

$m = \pm 9$

Step 4

The final answer is the combination of both solutions.

$m = 9, - 9$