Which set of coefficients of the terms in the expansion of the binomial (x+y)^3 is correct ?

We are technically FOILing this out... with a power of 3.

(x+y)(x+y)(x+y)

So we can first factor out the first two "x+y"s.

, multiplied by the last "x+y".



Coefficients are the number that comes in front of a variable. 

In this case, 1 comes in front of , 3 comes in front of , 3 comes in front of , and 1 comes in front of .

Thus: 1, 3, 3, 1.
         Answer Choice A