Solve Using the Quadratic Formula 5x^2+9x-2=0

$5 x^{2} + 9 x - 2 = 0$

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 $a = 5$ , $b = 9$ , and $c = - 2$ into the quadratic formula and solve for $x$ .

$\frac{- 9 \pm \sqrt{9^{2} - 4 \cdot (5 \cdot - 2)}}{2 \cdot 5}$

Step 3

Simplify.

Simplify the numerator.

Raise $9$ to the power of $2$ .

$x = \frac{- 9 \pm \sqrt{81 - 4 \cdot 5 \cdot - 2}}{2 \cdot 5}$

Multiply $- 4 \cdot 5 \cdot - 2$ .

Multiply $- 4$ by $5$ .

$x = \frac{- 9 \pm \sqrt{81 - 20 \cdot - 2}}{2 \cdot 5}$

Multiply $- 20$ by $- 2$ .

$x = \frac{- 9 \pm \sqrt{81 + 40}}{2 \cdot 5}$

Add $81$ and $40$ .

$x = \frac{- 9 \pm \sqrt{121}}{2 \cdot 5}$

Rewrite $121$ as $11^{2}$ .

$x = \frac{- 9 \pm \sqrt{11^{2}}}{2 \cdot 5}$

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

$x = \frac{- 9 \pm 11}{2 \cdot 5}$

Multiply $2$ by $5$ .

$x = \frac{- 9 \pm 11}{10}$

Step 4

The final answer is the combination of both solutions.

$x = \frac{1}{5}, - 2$