# Math Help - [SOLVED] domain of function

1. ## [SOLVED] domain of function

For the function f defined by f(x)=3x+4
9x-2

I know that for a I substitute x with -2. I just don't know how to solve b,c, & d. The letters are throwing me off.

a. f(-2)=
b. f(-x)=
c. -f(x)=
d. f(x+h)=

2. 9x-2 is supposed to be under 3x+4

3. Originally Posted by Ashley189
For the function f defined by f(x)=3x+4
9x-2

I know that for a I substitute x with -2. I just don't know how to solve b,c, & d. The letters are throwing me off.

a. f(-2)=
b. f(-x)=
c. -f(x)=
d. f(x+h)=

$f(x)=\frac{3x+4}{9x-2}$

(b) just replace x with -x like how you did for -2

(c) $f(x)=-\frac{3x+4}{9x-2}$

(d)replace x with x+h

4. To learn how to evaluate functions at variables or expressions (instead of only at a number), try some online lessons.

5. Stapel,

I got it now. Thanks!