Solve the inequality and graph the solution set on a real number line. Express the solution set in interval notation.

StartAbsoluteValue x squared plus 4 x minus 22 EndAbsoluteValue greater than 10
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Part 1
The solution set is
  
enter your response here.
​(Type your answer in interval notation. Use integers or fractions for any numbers in the​ expression.)

1 answer

To solve the inequality \( |x^2 + 4x - 22| > 10 \), we start by breaking it down into two cases based on the properties of absolute values.

Case 1:

\[ x^2 + 4x - 22 > 10 \]

Rearranging we have: \[ x^2 + 4x - 32 > 0 \]

Next, we can solve the corresponding quadratic equation: \[ x^2 + 4x - 32 = 0 \]

Using the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1, b = 4, c = -32 \): \[ x = \frac{-4 \pm \sqrt{4^2 - 4 \cdot 1 \cdot (-32)}}{2 \cdot 1} = \frac{-4 \pm \sqrt{16 + 128}}{2} = \frac{-4 \pm \sqrt{144}}{2} = \frac{-4 \pm 12}{2} \]

Calculating the two roots:

  1. \( x = \frac{8}{2} = 4 \)
  2. \( x = \frac{-16}{2} = -8 \)

Now, we can determine the intervals for which \( x^2 + 4x - 32 > 0 \): The roots divide the number line into intervals: \( (-\infty, -8) \), \( (-8, 4) \), and \( (4, \infty) \). We will test each interval:

  • For \( x = -9 \) (in \( (-\infty, -8) \)): \[ (-9)^2 + 4(-9) - 32 = 81 - 36 - 32 = 13 > 0 \quad \text{(True)} \]

  • For \( x = 0 \) (in \( (-8, 4) \)): \[ 0^2 + 4(0) - 32 = -32 < 0 \quad \text{(False)} \]

  • For \( x = 5 \) (in \( (4, \infty) \)): \[ 5^2 + 4(5) - 32 = 25 + 20 - 32 = 13 > 0 \quad \text{(True)} \]

So from Case 1, the solution is: \[ (-\infty, -8) \cup (4, \infty) \]

Case 2:

\[ -(x^2 + 4x - 22) > 10 \] This simplifies to: \[ -x^2 - 4x + 22 > 10 \]

Rearranging we get: \[ -x^2 - 4x + 12 > 0 \] or \[ x^2 + 4x - 12 < 0 \]

Solving the corresponding quadratic equation \( x^2 + 4x - 12 = 0 \): Using the quadratic formula again, where \( a = 1, b = 4, c = -12 \): \[ x = \frac{-4 \pm \sqrt{4^2 - 4 \cdot 1 \cdot (-12)}}{2 \cdot 1} = \frac{-4 \pm \sqrt{16 + 48}}{2} = \frac{-4 \pm \sqrt{64}}{2} = \frac{-4 \pm 8}{2} \]

Calculating the roots:

  1. \( x = \frac{4}{2} = 2 \)
  2. \( x = \frac{-12}{2} = -6 \)

The roots divide the number line into intervals: \( (-\infty, -6) \), \( (-6, 2) \), and \( (2, \infty) \). We test each interval:

  • For \( x = -7 \) (in \( (-\infty, -6) \)): \[ (-7)^2 + 4(-7) - 12 = 49 - 28 - 12 = 9 > 0 \quad \text{(False)} \]

  • For \( x = 0 \) (in \( (-6, 2) \)): \[ 0^2 + 4(0) - 12 = -12 < 0 \quad \text{(True)} \]

  • For \( x = 3 \) (in \( (2, \infty) \)): \[ 3^2 + 4(3) - 12 = 9 + 12 - 12 = 9 > 0 \quad \text{(False)} \]

So from Case 2, the solution is: \[ (-6, 2) \]

Final Solution:

Combining both cases, the overall solution is: \[ (-\infty, -8) \cup (-6, 2) \cup (4, \infty) \]

In interval notation, the solution set is: \[ \boxed{(-\infty, -8) \cup (-6, 2) \cup (4, \infty)} \]

Graphing the solution set:

You would represent this on a number line with open circles at points \(-8\), \(-6\), \(2\), and \(4\), shading the intervals that are included in the solution set.