I am doing an Algebra course (UC Irvine / Coursera), and am having a bit of trouble understanding the following property:
$$ 3(x+h)^2 $$
Seems to be distributed as such:
$$ 3(x^2+2xh+h^2) $$
.. now, due to the distributive property, I understand why the x^2 and h^2 are so, but I have no idea where the "extra" 2xh came from. I've been grappling with the fact that while the original quantity can be represented as,
$$ 3(x+h)(x+h) $$
..it's just not clear to me how the 2xh is "created".
Any advice on this would be appreciated.
NB: This is not an assignment; it's from Week 2, Lecutre "Multiple Operations with Polynomials", at about 5:30.