.
|x+2|<2x+7.
~~~~~~~~~~~~~~~~~~~~
|x+2|<2x+7. (1)
1. If x+2 >= 0, then |x+2| = x+2.
Hence, in the domain x >= -2 the inequality (1) takes the form
x + 2 < 2x + 7, or 2-7 < x, which is x > -5.
In other words, in the domain x >= -2 the solution set is x > -5.
Thus for the domain x > -2 the solution set is the intersection [
,
) and (
,
), i.e. [
,
).
2. If x+2 < 0, then |x+2| = -(x+2).
Hence, in the domain x < -2 the inequality (1) takes the form
-(x + 2) < 2x + 7, or -x - 2 < 2x +7, or -2-7 < 3x, or -9 < 3x, which is x > -3.
In other words, in the domain x < -2 the solution set is x > -3.
Thus for the domain x < -2 the solution set is the intersection (
,
) and (
,
), i.e. (
,
).
3. Finally, combining these two cases, we obtain the solution set as (
,
) U [
,
, i.e. (
,
).
Answer. The solution set to inequality (1) is (
,
).
Plots y = |x+2| and y = 2x+7