# What does the "set R- {-1}" mean??? [closed]

I am trying to answer the question: On the set R-{-1} define the operations a⊕b=a+b+aba⊕b=a+b+ab and axb=0axb=0. Determine if (R - {-1}, ⊕, x) is a ring. Is it a commutative ring with unity?

However I have no idea what this set even is/looks like. Any help is greatly appreciated!

• you posted the same question 43 min ago. why do you post again ? Apr 5 '16 at 1:42
• Possible duplicate of Determine if R is a commutative ring with unity?
– user296602
Apr 5 '16 at 6:12

The notation $R-\{-1\}$ means the same thing as $R\setminus \{-1\}$. They both denote the set $\{x\in R\mid x\neq -1\}$.
(In general, $A - B$ and $A\setminus B$ are notations for the set $\{x\mid x\in A\text{ and }x\notin B\}$.)