Plane geometry question

QUESTION: The equation of the plane ABC is 6x + 3y + 2z = 6. Put the equation in the form f(x,y,z) = 1.

I am not sure what the form f(x,y,z) actually means. Can anybody enlighten me?

f(x,y,z) just means put it in the form of a function in terms of the variables x, y and z. for f(x,y,z) = 1, just divide the intitial form by 6 to get f(x,y,z) = x + y/2 +z/3 = 1