In the like terms column, the variables (the letters you see next to the numbers) are the same, and if they have an exponent the exponent is the same number too.
In the unlike terms column, they have different variables which means you can’t add or subtract them together. They also have different exponents, so you can’t add or subtract them either.
The coefficients can be different, but the variable and the degree of the variable must remain the same in order for it to be considered like terms. Hope this helped!