Which of the Following Is a Linear Function?
A) $f ( x ) = 2 - 7 x$

Multiple Choice

Which of the following is a linear function?

A) $f ( x ) = 2 - 7 x$
B) $f ( x ) = 2 + x + x ^ { 2 }$
C) $f ( x ) = \sqrt { 2 x + 7 }$
D) $f ( x ) = \frac { 2 } { x } + 7$