Like terms are a pair of numbers with the same base and exponent. So an example of a like term would be 2x+4x <-- these are like terms because they have the same base (x) and the same exponent (1)...
Yep! Because with a little rearrangement, this 4ba becomes 4ab. You can do this because, well, in multiplication this works. I mean, 2 x 3 is the same as 3 x 2 right? So to be like terms you have to...