what are like terms and why are they used because i need to write a page of notes and i am only give a few sentences?

Answer 1

like terms are terms that look the same.

ex: 2x+3-2=12
the +3 and the -2 are like terms so you can combine them together.
2x-1=12

Answer 2

it would actually be 2x+1 not 2x-1 because +3-2 is equal to +1.
and yes you can combine them together.