In the 2nd step how did |r2 - r1| get cubed instead of getting squared - Physics - Electric Charges And Fields

Question

In the 2nd step how did
|r2 - r1| get
cubed instead of getting squared ?

Kuldeep Chhimpa · Accepted Answer

In the 2nd step how did |r2 - r1| get cubed instead of getting squared ?