I tried solving an exercise and was unsuccessful in doing so. I checked the solution and it had this piece $a^3 + b^3 = (a+b)^3-3ab(a+b)$.
Another exercise also had a similar formula: $a^2+b^2=(a+b)^2 - 2ab$
I can see a similar pattern but it's pointless to study the pattern if I don't understand it at all. Is this some kind of special product?