What does the * mean?
2 answers:
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Answer:
Option (2)
Step-by-step explanation:
To find the solution set of the given inequality we will follow the following steps.
1). Convert the inequality into an equation.
2). Find the solutions from the equation.
3). Check these solutions and intervals on a number line.
Given inequality is 5(x - 2)(x + 4) > 0
Step 1. Equation for given inequality is,
5(x - 2)(x + 4) = 0
Step 2. Solutions for the given equation will be,
(x - 2) = 0 ⇒ x = 2
(x + 4) = 0 ⇒ x = -4
Step 3. Therefore, there will be two critical points on the number line,
x = 2, x = -4
Now we will check the solutions of the given inequality in the given intervals,
x < -4, -4 < x < 2 and x > 2
For x < -4,
Let the solution is x = -5
5(x + 4)(x - 2) = 5(-5 + 4)(-4 - 2)
= 30 > 0
Therefore, x < -4 will be the solution area of the inequality.
For -4 < x < 2,
Let the solution is x = 0
5(x + 4)(x - 2) = 5(0 + 4)(0 - 2)
= -40 < 0
Therefore, -4 < x < 2 will not be the solution set for the given inequality.
For x > 2,
Let the solution is x = 3
5(x + 4)(x - 2) = 5(3 + 4)(3 - 2)
= 35 > 0
Therefore, x > 2 will be the solution area of the inequality.
Summarizing all steps we find that the solution set of the inequality is,
{x | x < -4 Or x > 2}
Option (2) will be the answer.
