Hi, I was working through some exercises and came to this:

$\displaystyle (x^2+y)^7$

I got an answer which starts out as:

$\displaystyle x^{14}+7x^{12}y+21x^{10}y^2$....

etc. etc.

but the textbook answer begins:

$\displaystyle x^{14}+7x^{12}+21x^{10}y^2$.....

note the missing $\displaystyle y$ from the "$\displaystyle 7x^{12}$" part.

This seems kooky to me, am I wrong or is the book wrong? And if I'm wrong, what did I do wrong?