Solve Using the Square Root Property 2a^2+98=0

$2 a^{2} + 98 = 0$

Step 1

Subtract $98$ from both sides of the equation.

$2 a^{2} = - 98$

Step 2

Divide each term in $2 a^{2} = - 98$ by $2$ and simplify.

Divide each term in $2 a^{2} = - 98$ by $2$ .

$\frac{2 a^{2}}{2} = \frac{- 98}{2}$

Simplify the left side.

Cancel the common factor of $2$ .

Cancel the common factor.

$\frac{2 a^{2}}{2} = \frac{- 98}{2}$

Divide $a^{2}$ by $1$ .

$a^{2} = \frac{- 98}{2}$

Simplify the right side.

Divide $- 98$ by $2$ .

$a^{2} = - 49$

Step 3

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$a = \pm \sqrt{- 49}$

Step 4

Simplify $\pm \sqrt{- 49}$ .

Rewrite $- 49$ as $- 1 (49)$ .

$a = \pm \sqrt{- 1 (49)}$

Rewrite $\sqrt{- 1 (49)}$ as $\sqrt{- 1} \cdot \sqrt{49}$ .

$a = \pm \sqrt{- 1} \cdot \sqrt{49}$

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

$a = \pm i \cdot \sqrt{49}$

Rewrite $49$ as $7^{2}$ .

$a = \pm i \cdot \sqrt{7^{2}}$

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

$a = \pm i \cdot 7$

Move $7$ to the left of $i$ .

$a = \pm 7 i$

Step 5

The complete solution is the result of both the positive and negative portions of the solution.

First, use the positive value of the $\pm$ to find the first solution.

$a = 7 i$

Next, use the negative value of the $\pm$ to find the second solution.

$a = - 7 i$

The complete solution is the result of both the positive and negative portions of the solution.

$a = 7 i, - 7 i$