Solve the Inequality for x x^2+4x-12>0

$x^{2} + 4 x - 12 > 0$

Convert the inequality to an equation.

$x^{2} + 4 x - 12 = 0$

Factor $x^{2} + 4 x - 12$ using the AC method.

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 12$ and whose sum is $4$ .

$- 2, 6$

Write the factored form using these integers.

$(x - 2) (x + 6) = 0$

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x - 2 = 0$

$x + 6 = 0$

Set $x - 2$ equal to $0$ and solve for $x$ .

Set $x - 2$ equal to $0$ .

$x - 2 = 0$

Add $2$ to both sides of the equation.

$x = 2$

Set $x + 6$ equal to $0$ and solve for $x$ .

Set $x + 6$ equal to $0$ .

$x + 6 = 0$

Subtract $6$ from both sides of the equation.

$x = - 6$

The final solution is all the values that make $(x - 2) (x + 6) = 0$ true.

$x = 2, - 6$

Use each root to create test intervals.

$x < - 6$

$- 6 < x < 2$

$x > 2$

Choose a test value from each interval and plug this value into the original inequality to determine which intervals satisfy the inequality.

Test a value on the interval $x < - 6$ to see if it makes the inequality true.

Choose a value on the interval $x < - 6$ and see if this value makes the original inequality true.

$x = - 8$

Replace $x$ with $- 8$ in the original inequality.

${(- 8)}^{2} + 4 (- 8) - 12 > 0$

The left side $20$ is greater than the right side $0$ , which means that the given statement is always true.

True

Test a value on the interval $- 6 < x < 2$ to see if it makes the inequality true.

Choose a value on the interval $- 6 < x < 2$ and see if this value makes the original inequality true.

$x = 0$

Replace $x$ with $0$ in the original inequality.

${(0)}^{2} + 4 (0) - 12 > 0$

The left side $- 12$ is not greater than the right side $0$ , which means that the given statement is false.

False

Test a value on the interval $x > 2$ to see if it makes the inequality true.

Choose a value on the interval $x > 2$ and see if this value makes the original inequality true.

$x = 4$

Replace $x$ with $4$ in the original inequality.

${(4)}^{2} + 4 (4) - 12 > 0$

The left side $20$ is greater than the right side $0$ , which means that the given statement is always true.

True

Compare the intervals to determine which ones satisfy the original inequality.

$x < - 6$ True

$- 6 < x < 2$ False

$x > 2$ True

$x < - 6$ True

$- 6 < x < 2$ False

$x > 2$ True

The solution consists of all of the true intervals.

$x < - 6$ or $x > 2$

The result can be shown in multiple forms.

Inequality Form:

$x < - 6 or x > 2$

Interval Notation:

$(- \infty, - 6) \cup (2, \infty)$

Solve the Inequality for x x^2+4x-12>0

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