Solve Using the Quadratic Formula 49x^2-9=0

$49 x^{2} - 9 = 0$

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 $a = 49$ , $b = 0$ , and $c = - 9$ into the quadratic formula and solve for $x$ .

$\frac{0 \pm \sqrt{0^{2} - 4 \cdot (49 \cdot - 9)}}{2 \cdot 49}$

Step 3

Simplify.

Simplify the numerator.

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

$x = \frac{0 \pm \sqrt{0 - 4 \cdot 49 \cdot - 9}}{2 \cdot 49}$

Multiply $- 4 \cdot 49 \cdot - 9$ .

Multiply $- 4$ by $49$ .

$x = \frac{0 \pm \sqrt{0 - 196 \cdot - 9}}{2 \cdot 49}$

Multiply $- 196$ by $- 9$ .

$x = \frac{0 \pm \sqrt{0 + 1764}}{2 \cdot 49}$

Add $0$ and $1764$ .

$x = \frac{0 \pm \sqrt{1764}}{2 \cdot 49}$

Rewrite $1764$ as $42^{2}$ .

$x = \frac{0 \pm \sqrt{42^{2}}}{2 \cdot 49}$

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

$x = \frac{0 \pm 42}{2 \cdot 49}$

Multiply $2$ by $49$ .

$x = \frac{0 \pm 42}{98}$

Simplify $\frac{0 \pm 42}{98}$ .

$x = \frac{\pm 3}{7}$

Step 4

The final answer is the combination of both solutions.

$x = \frac{3}{7}, - \frac{3}{7}$