Like & Unlike Terms –
Terms which are alike or similar or identical in their variables are called like terms. Terms which are not like will be called unlike terms.
Example.1) 2/3 ab, - 7/9 ab, 12 ab are like terms
Example.2) 4/5 a, - 8 b, 26 ab are unlike terms
Example.3) 11 x⁵, - 12 xy, 7 y² are unlike terms.
Example.4) 8 x²y, 7 xy⁴, - 9 x⁴y⁵ are unlike terms.