If f(x) is a linear function, which statement must be true?
f(x) has no constant term.
f(x) has no x2-term.
f(x) has no terms with a coefficient other than 1.
f(x) has no x-term.

The standard equation for a linear function is given by:
 
  where,
  m: slope of the line
  b: cutting point with the y-axis (constant term)
  x: independent variable (grade 1 in the exponent)
  f (x): dependent variable
  the values of m can be all real numbers
  the values of b can be all real numbers
  answer:
  a statement that must be true is:
  f (x) has not x2-term.

The correct answer is the second option.  if f(x) is a linear function,  f(x) has no x^2-term. the general equation of a linear function has the highest degree of a polynomial of 1. the general equation is expressed as: f(x) = mx+b where m is the slope of the line and b is the point where the line passes through the y-axis when x is 0 or it is the y-intercept.