To solve this one you have to find the ones that are connected by variables or look the same
For example.
1x and 2x are like terms because they have the same variable X
4d and 6/2d are like terms because they have the same variable D
4 and 3 are like terms because they have no variables, and they are the same
So now that you understand what like terms are you may so it
1/2 and 2s are like terms because they share the same variable S
6u and 9u are like terms because they share the same variable U
I hope this helped and if it's wrong blame me
Ps. Brainlist would really help