Question 475236
f(x)= x+10 
find f(-4), and f(x+8)

<pre>
Here is how to find f(-4):

1. Start with 

f(x) = x + 10

2. Erase the x's and put a blank where the x's were.  Now you have

f(__) =  __ + 10

3. Put -4 in the blanks:

f(<u>-4</u>) =  <u>-4</u> + 10

Take away the underlines:

f(-4) = -4 + 10

Combine the numbers on the right:

f(-4) = 6

That's it.  It's just a substitution problem.  You look in the
parentheses after the f and whatever is in there tells you what to
substitute for x in the right side.  Then you simplify the right
side.

-----------------------

Here is how to find f(x+8):

1. Start with 

f(x) = x + 10

2. Erase the x's and put a blank where the x's were.  Now you have

f(___) =  ___ + 10

3. Put x+8 in the blanks:

f(<u>x+8</u>) =  <u>x+8</u> + 10

Take away the underlines:

f(x+8) = x+8 + 10

Combine the numbers on the right:

f(-4) = x + 18

That's it.  It's just a substitution problem.  You look in the
parentheses after the f.  Whatever is in there tells you what to
substitute for x in the right side.  So you substitute and simplify
the right side.

Don't try to make it hard.  Just substitute for x whatever number,
letter of expression that's in the parentheses after the f, then
simplify.  What could be easier?

Edwin</pre>