Textbook Problem

In each of 7-14, the relation R is an equivalence relation on the set A. Find the distinct equivalence classes of R. $X=\left\{-1,01\right\}$ and $A=P\left(X\right)$ ,R is defined on $P\left(X\right)$ as follows: For all sets s r in $P\left(X\right)$ ,
$sRr\iff \text{the}\text{sum}\text{of the elements in }s\text{equals the sum of the elements in }r.$