Originally posted by noble
the function that he specified is not necessarily f(x,y,z)

f(x) simply says that it's a function which has x as a dependant
variable.

f(x) = 79x+y+7z, z and y could be constants if it's a function
with respect to x
Yeah, possibly, but generally, letters nearer the end of the alphabet are used as variables i.e. x, y, z, while letters such as A, B, C are used to represent constants.