Which one(s) of the following functions is linear?

a) .

b) .

c) .

d) .

e) .

f) .

g) .

h) .

i) .

j) .

k) . ( is an arbitrary constant).

**Solution**

a) Linear

b) Linear

c) Linear

d) Nonlinear

e) Linear

f) Nonlinear

g) Nonlinear

h) Nonlinear

i) Nonlinear

j) Linear

k) Linear