Solve the Inequality for x 4-x^2<=0

$4 - x^{2} \leq 0$

Step 1

Subtract $4$ from both sides of the inequality.

$- x^{2} \leq - 4$

Step 2

Divide each term in $- x^{2} \leq - 4$ by $- 1$ and simplify.

Divide each term in $- x^{2} \leq - 4$ by $- 1$ . When multiplying or dividing both sides of an inequality by a negative value, flip the direction of the inequality sign.

$\frac{- x^{2}}{- 1} \geq \frac{- 4}{- 1}$

Simplify the left side.

Dividing two negative values results in a positive value.

$\frac{x^{2}}{1} \geq \frac{- 4}{- 1}$

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

$x^{2} \geq \frac{- 4}{- 1}$

Simplify the right side.

Divide $- 4$ by $- 1$ .

$x^{2} \geq 4$

Step 3

Take the square root of both sides of the inequality to eliminate the exponent on the left side.

$\sqrt{x^{2}} \geq \sqrt{4}$

Step 4

Simplify the equation.

Simplify the left side.

Pull terms out from under the radical.

$| x | \geq \sqrt{4}$

Simplify the right side.

Simplify $\sqrt{4}$ .

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

$| x | \geq \sqrt{2^{2}}$

Pull terms out from under the radical.

$| x | \geq | 2 |$

The absolute value is the distance between a number and zero. The distance between $0$ and $2$ is $2$ .

$| x | \geq 2$

Step 5

Write $| x | \geq 2$ as a piecewise.

To find the interval for the first piece, find where the inside of the absolute value is non-negative.

$x \geq 0$

In the piece where $x$ is non-negative, remove the absolute value.

$x \geq 2$

To find the interval for the second piece, find where the inside of the absolute value is negative.

$x < 0$

In the piece where $x$ is negative, remove the absolute value and multiply by $- 1$ .

$- x \geq 2$

Write as a piecewise.

${\begin{cases} x \geq 2 & x \geq 0 \\ - x \geq 2 & x < 0 \end{cases}$

Step 6

Find the intersection of $x \geq 2$ and $x \geq 0$ .

$x \geq 2$

Step 7

Divide each term in $- x \geq 2$ by $- 1$ and simplify.

Divide each term in $- x \geq 2$ by $- 1$ . When multiplying or dividing both sides of an inequality by a negative value, flip the direction of the inequality sign.

$\frac{- x}{- 1} \leq \frac{2}{- 1}$

Simplify the left side.

Dividing two negative values results in a positive value.

$\frac{x}{1} \leq \frac{2}{- 1}$

Divide $x$ by $1$ .

$x \leq \frac{2}{- 1}$

Simplify the right side.

Divide $2$ by $- 1$ .

$x \leq - 2$

Step 8

Find the union of the solutions.

$x \leq - 2$ or $x \geq 2$

Step 9

The result can be shown in multiple forms.

Inequality Form:

$x \leq - 2 or x \geq 2$

Interval Notation:

$(- \infty, - 2] \cup [2, \infty)$

Step 10

Solve the Inequality for x 4-x^2<=0

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