Solve Using the Quadratic Formula 3x(x+2)=5

$3 x (x + 2) = 5$

Step 1

Move all terms to the left side of the equation and simplify.

Simplify the left side.

Simplify $3 x (x + 2)$ .

Apply the distributive property.

$3 x \cdot x + 3 x \cdot 2 = 5$

Multiply $x$ by $x$ by adding the exponents.

Move $x$ .

$3 (x \cdot x) + 3 x \cdot 2 = 5$

Multiply $x$ by $x$ .

$3 x^{2} + 3 x \cdot 2 = 5$

Multiply $2$ by $3$ .

$3 x^{2} + 6 x = 5$

Subtract $5$ from both sides of the equation.

$3 x^{2} + 6 x - 5 = 0$

Step 2

Use the quadratic formula to find the solutions.

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

Step 3

Substitute the values $a = 3$ , $b = 6$ , and $c = - 5$ into the quadratic formula and solve for $x$ .

$\frac{- 6 \pm \sqrt{6^{2} - 4 \cdot (3 \cdot - 5)}}{2 \cdot 3}$

Step 4

Simplify.

Simplify the numerator.

Raise $6$ to the power of $2$ .

$x = \frac{- 6 \pm \sqrt{36 - 4 \cdot 3 \cdot - 5}}{2 \cdot 3}$

Multiply $- 4 \cdot 3 \cdot - 5$ .

Multiply $- 4$ by $3$ .

$x = \frac{- 6 \pm \sqrt{36 - 12 \cdot - 5}}{2 \cdot 3}$

Multiply $- 12$ by $- 5$ .

$x = \frac{- 6 \pm \sqrt{36 + 60}}{2 \cdot 3}$

Add $36$ and $60$ .

$x = \frac{- 6 \pm \sqrt{96}}{2 \cdot 3}$

Rewrite $96$ as $4^{2} \cdot 6$ .

Factor $16$ out of $96$ .

$x = \frac{- 6 \pm \sqrt{16 (6)}}{2 \cdot 3}$

Rewrite $16$ as $4^{2}$ .

$x = \frac{- 6 \pm \sqrt{4^{2} \cdot 6}}{2 \cdot 3}$

Pull terms out from under the radical.

$x = \frac{- 6 \pm 4 \sqrt{6}}{2 \cdot 3}$

Multiply $2$ by $3$ .

$x = \frac{- 6 \pm 4 \sqrt{6}}{6}$

Simplify $\frac{- 6 \pm 4 \sqrt{6}}{6}$ .

$x = \frac{- 3 \pm 2 \sqrt{6}}{3}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$x = \frac{- 3 \pm 2 \sqrt{6}}{3}$

Decimal Form:

$x = 0.63299316 \dots, - 2.63299316 \dots$

Solve Using the Quadratic Formula 3x(x+2)=5

Related Questions

Support LCMGCF.com by disabling your adblocker.