Question
Solve each absolute value inequality. Graph the solution:
Hint:
|x| is known as the absolute value of x. It is the non-negative value of x irrespective of its sign. The value of absolute value of x is given by
First, we simplify the inequality and then solve it by considering the two cases. Then we plot the graph on the x- axis, or the real line R in such a way that the graph satisfies the value of x from both the cases.
The correct answer is: Combining the above two solutions, we get x ≤ - 7 and x ≥ - 1
Step by step solution:
The given inequality is
2|x + 4| ≤ - 6
Dividing by 2 throughout, we get
-|x + 4 |≤ - 3
Multiplying by -1, we have
|x + 4| ≥ 3
We use the definition of , which is
For, x + 4 < 0,
We have
|x + 4| = - (x + 4) ≥ 3
Simplifying, we get
- x - 4 ≥ 3
Adding 4 on both sides, we get
x ≥ 3 + 4
Multiplying on both sides, we have
x ≤ - 7
For We have
|x + 4|= x + 4 ≥ 3
Subtracting 4 from both sides, we get
x ≥ 3 - 4
Combining the above two solutions, we get
x ≤ - 7 and x ≥ -1
We plot the above inequality on the real line.
The points -7 and -1 are included in the graph.
Dividing by 2 throughout, we get
Multiplying by -1, we have
We use the definition of , which is
We have
Simplifying, we get
Adding 4 on both sides, we get
Multiplying on both sides, we have
For We have
Subtracting 4 from both sides, we get
Combining the above two solutions, we get
We plot the above inequality on the real line.
The points -7 and -1 are included in the graph.
The given inequality contains only one variable. So, the graph is plotted on one dimension, which is the real line. Geometrically, the absolute value of a number may be considered as its distance from zero regardless of its direction. The symbol |.| is pronounced as ‘modulus’. We read |x| as ‘modulus of x’ or ‘mod x’.