What's the coefficient of xy in the expansion of (3x + 3y + 3)^3?
Applying the binomial formula and distributing everything out (I have no life), we get
\(27x^{3}+81x^{2}y+81xy^{2}+27y^{3}+81x^{2}+162xy+81y^{2}+81x+81y+27 \)
As shown, 162 is the coefficient.
Thanks! :)
+1897 
