How come sometimes (a+b)^2= a^2+b^2. While other times it equals (a+b)(a+b)
Kinda silly question probably, but I know sometimes
(a+b)2 = a2+b2. While other times (a+b)2 = (a+b)(a+b).
I had to make (x+3)2 = (x+3)(x+3). I started to wonder why it wouldn’t be x2 + 9 since when I look at the rules of exponents it almost always shows the a2 + b2 rule.
Hope this makes sense, but thanks in advance!