Answer:
{-1, 2}
Step-by-step explanation:
The quantity x + 1 changes sign at x = -1; equivalently, x + 1 = 0 when x = -1.
If x = -1, then |x+1|+|x−2|=3 becomes |-1 + 1| + |-1 −2|=3, which is TRUE. So x = -1 is a solution.
If x = 2, then we have the equation |2 + 1| + |2 − 2|=3, or |2 + 1| = 3, which is TRUE. So x = 2 is also a solution.
