Solve Using the Quadratic Formula 3x^2+5x-12=0

$3 x^{2} + 5 x - 12 = 0$

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 $a = 3$ , $b = 5$ , and $c = - 12$ into the quadratic formula and solve for $x$ .

$\frac{- 5 \pm \sqrt{5^{2} - 4 \cdot (3 \cdot - 12)}}{2 \cdot 3}$

Step 3

Simplify.

Simplify the numerator.

Raise $5$ to the power of $2$ .

$x = \frac{- 5 \pm \sqrt{25 - 4 \cdot 3 \cdot - 12}}{2 \cdot 3}$

Multiply $- 4 \cdot 3 \cdot - 12$ .

Multiply $- 4$ by $3$ .

$x = \frac{- 5 \pm \sqrt{25 - 12 \cdot - 12}}{2 \cdot 3}$

Multiply $- 12$ by $- 12$ .

$x = \frac{- 5 \pm \sqrt{25 + 144}}{2 \cdot 3}$

Add $25$ and $144$ .

$x = \frac{- 5 \pm \sqrt{169}}{2 \cdot 3}$

Rewrite $169$ as $13^{2}$ .

$x = \frac{- 5 \pm \sqrt{13^{2}}}{2 \cdot 3}$

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

$x = \frac{- 5 \pm 13}{2 \cdot 3}$

Multiply $2$ by $3$ .

$x = \frac{- 5 \pm 13}{6}$

Step 4

The final answer is the combination of both solutions.

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