Solve Using the Quadratic Formula 5x^2-11x-12=0

$5 x^{2} - 11 x - 12 = 0$

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 $a = 5$ , $b = - 11$ , and $c = - 12$ into the quadratic formula and solve for $x$ .

$\frac{11 \pm \sqrt{{(- 11)}^{2} - 4 \cdot (5 \cdot - 12)}}{2 \cdot 5}$

Step 3

Simplify.

Simplify the numerator.

Raise $- 11$ to the power of $2$ .

$x = \frac{11 \pm \sqrt{121 - 4 \cdot 5 \cdot - 12}}{2 \cdot 5}$

Multiply $- 4 \cdot 5 \cdot - 12$ .

Multiply $- 4$ by $5$ .

$x = \frac{11 \pm \sqrt{121 - 20 \cdot - 12}}{2 \cdot 5}$

Multiply $- 20$ by $- 12$ .

$x = \frac{11 \pm \sqrt{121 + 240}}{2 \cdot 5}$

Add $121$ and $240$ .

$x = \frac{11 \pm \sqrt{361}}{2 \cdot 5}$

Rewrite $361$ as $19^{2}$ .

$x = \frac{11 \pm \sqrt{19^{2}}}{2 \cdot 5}$

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

$x = \frac{11 \pm 19}{2 \cdot 5}$

Multiply $2$ by $5$ .

$x = \frac{11 \pm 19}{10}$

Step 4

The final answer is the combination of both solutions.

$x = 3, - \frac{4}{5}$