we add like terms so remembe that we can add the numbers in front of the placeholders exg 3a+2a=5a becuase 3+2=5 we cannot add a+b so remember the associative property which is a+(b+c)=(a+b)+c therefor we can move the parenthasees also remember the commutativer property which is a+b=b+a so we can change (3a-b)+2a to (3a+2a)-b=(5a)-b=5a-b
