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 ≥ 2
Step by step solution:
The given inequality is
|2 x + 5| ≥ 9
We use the definition of , which is
For, 2x + 5 < 0,
We have
|2x + 5| = - (2x + 5) ≥ 9
Simplifying, we get
-2x – 5 ≥ 9
Adding 5 on both sides, we get
-2x ≥ 9 + 5
Dividing by 2 on both sides, we get
-x ≥ 7
Multiplying on both sides, we have
X ≤ - 7
For, x ≥ 0,
We have
|2x + 5| = 2x + 5 ≥
Subtracting 5 from both sides, we get
2x ≥ 9 - 5
Dividing by 2 throughout, we get
X ≥ 2
Combining the above two solutions, we get
X ≤ - 7 and x ≥ 2
We plot the above inequality on the real line.
The points -7 and 2 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’.