hi, ive just been reading through this website on differentiation, anyway ive just come across subtraction and addition of functions, KryssTal : Introduction to Calculus theres the link, if you scroll down about 1/4 of the way down you will see the section i am talking about, can anyone explain this a bit easier i cant seem to grasp the concept, especially when i was following an example;(i) For the functiony = 4x2 + 2x + 3, the derivative isdy/dx = 8x + 2

now i cantsee where the 2 has come from, i get the 8x part but not the second bit.

please help.