|a|-|b|≤|a-b|≤|a|+|b|
|z|-|2+2i|≤|z-(2+2i)|≤|z|+|2+2i|
|z|-2√2≤√2≤|z|+2√2
-2√2-√2≤-|z|≤2√2-√2
√2≤|z|≤3≤3√2