Please help ;-;, it's math and i suck at it

Write the expression in simplified radical form. show all steps and work including any foil method work. (hint: use the conjugate. no decimal answers.) (9-2√3)/(12+√3)

What are “like terms”? why can we only add like terms?

The constant of proportionality is always the where k is the constant of proportionality. additionally, you can find the constant of proportionality by finding the ratio for any point onasap