Question

How do you solve `|a+1|\le 4`?

Answer 1

`-5\le a\le 3`

Explanation:

By definition, `|x|\le k \iff -k \le x \le k`

So, `|a+1|\le 4 \iff -4 \le a+1 \le 4`

Subtract `1` from all sides to get

`-5\le a\le 3`