Solve Using the Quadratic Formula 2x^2-8x+10=0

$2 x^{2} - 8 x + 10 = 0$

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 $a = 2$ , $b = - 8$ , and $c = 10$ into the quadratic formula and solve for $x$ .

$\frac{8 \pm \sqrt{{(- 8)}^{2} - 4 \cdot (2 \cdot 10)}}{2 \cdot 2}$

Step 3

Simplify.

Simplify the numerator.

Raise $- 8$ to the power of $2$ .

$x = \frac{8 \pm \sqrt{64 - 4 \cdot 2 \cdot 10}}{2 \cdot 2}$

Multiply $- 4 \cdot 2 \cdot 10$ .

Multiply $- 4$ by $2$ .

$x = \frac{8 \pm \sqrt{64 - 8 \cdot 10}}{2 \cdot 2}$

Multiply $- 8$ by $10$ .

$x = \frac{8 \pm \sqrt{64 - 80}}{2 \cdot 2}$

Subtract $80$ from $64$ .

$x = \frac{8 \pm \sqrt{- 16}}{2 \cdot 2}$

Rewrite $- 16$ as $- 1 (16)$ .

$x = \frac{8 \pm \sqrt{- 1 \cdot 16}}{2 \cdot 2}$

Rewrite $\sqrt{- 1 (16)}$ as $\sqrt{- 1} \cdot \sqrt{16}$ .

$x = \frac{8 \pm \sqrt{- 1} \cdot \sqrt{16}}{2 \cdot 2}$

Rewrite $\sqrt{- 1}$ as $i$ .

$x = \frac{8 \pm i \cdot \sqrt{16}}{2 \cdot 2}$

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

$x = \frac{8 \pm i \cdot \sqrt{4^{2}}}{2 \cdot 2}$

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

$x = \frac{8 \pm i \cdot 4}{2 \cdot 2}$

Move $4$ to the left of $i$ .

$x = \frac{8 \pm 4 i}{2 \cdot 2}$

Multiply $2$ by $2$ .

$x = \frac{8 \pm 4 i}{4}$

Simplify $\frac{8 \pm 4 i}{4}$ .

$x = 2 \pm i$