# If in Ring, evaluate (a+b)(c+d)

1. Homework Statement

If a,b,c,d $$\in$$ R, evaluate (a+b)(c+d). (R is a ring.

2. Homework Equations

3. The Attempt at a Solution

I think that it's simple foiling, but I'm not sure.

Related Calculus and Beyond Homework Help News on Phys.org
Why would you suspect this not to be true?

If you're in doubt re-check the defintion of a ring.

Last edited:
I doubt it simply because I'm in a 4000 level Math course. It can't be this easy an answer.

Dick
Homework Helper
What else could it be?

Well, if there's no more information about a,b,c,d than I don't know what else you could do

Okay, so I'm going to guess that everyone agrees with me that this is right? It just seems too easy! Oh well, I'll accept it and move on. :-D

Treat (a+d) as one element and use the distributive property of rings. Then use it again. Make sure you keep the ordering if you're not dealing with a commutative ring.

Okay, that makes sense, PingPong! So, technically, the order is different.

(a+b)(c+d)
=> (a+b)c+(a+b)d