Mmm, Some of your answers I agree with Max but some are open to interpretation.
Which of these functions is a linear function?
a. f(x) = 2x2 yes defintely NOT a lnear graph.
Linear graphs cannot have x raised to any power (except 1 which is invisable)
b. f(x) = (1 / 2)2x = \((\frac{1}{2})^2x = \frac{1}{4}x=0.25x \qquad \mbox{YES this is definitely a LINEAR equation}\)
c. f(x) = 1 / 2x
If you mean f(x)=1/(2x) then it is not linear becasue x cannot be on the bottom.
If you mean (1/2)*x then it IS LINEAR
d. f(x) = - 1 / 2(x - 2)
If you mean\( f(x)=\frac{-1}{2(x-2)}\)
then it is NOT linear becasue x cannot be on the bottom.
If you mean \( f(x)=\frac{-1}{2}(x-2)\)
then it IS LINEAR