Question

What is the Value of f(6) if f(x)=2x-11

Answer 1

The answers are
f
o
g
(
x
)
=
−
2
x
+
23
and
g
o
f
(
x
)
=
−
2
x
+
5

Explanation:
f
(
x
)
=
−
2
x
+
11

g
(
x
)
=
x
−
6

f
o
g
(
x
)
=
f
(
g
(
x
)
)
=
f
(
x
−
6
)
=
−
2
(
x
−
6
)
+
11

=
−
2
x
+
12
+
11
=
−
2
x
+
23

g
o
f
(
x
)
=
g
(
f
(
x
)
)
=
g
(
−
2
x
+
11
)
=
−
2
x
+
11
−
6

=
−
2
x
+
5

I think that the equations speak by themselves.
Of course,
f
o
g
(
x
)
≠
g
o
f
(
x
)

Answer 2

Answer:

f(x)=2x-11

f(6)=2(6)-11

    =12-11

    =1

and the answer is c.

Explanation:

f(6) means you have to replace all x's in the function with 6.

For example, if the problem was asking you what is the value of f(10) you would have to replace all the x's in the respective function with 10 and so on.