Which function is linear?

A) f(x) =
3
2x
+
1
2
B) f(x) = |
3
2
x| +
1
2
C) f(x) = (
3
2
x)2 +
1
2
D) f(x) =
3
2
x −
1
2

Ten members of balin's soccer team ran warm ups for practice. each member ran the same distance. their combined distance was 5/6 of a mile. to find the distance that each member ran, balin wrote the expression below.