Hello,

My professor gave us a sample worksheet on function domains to use as a study guide for our exam tomorrow, but didn't give us an answer key (so it's really quite useless)! I can't seem to get ahold of her, so I thought I'd post it on here and see if I could get some answers!

Find the domain of the following:

1.) f(x) = 5x-2/7-11x

2.) f(x) = 3-x/x^2+4x+3

3.) f(x) = x^2-9

4.) f(x) = square root of 5-2x

5.) f(x) = cube root of 3x-1

6.) f(x) = 5x+1/eighth root of x-4

7.) f(x) = x+2/seventh root of 5x-10

8.) f(x) = square root of x^2-81

9.) f(x) = square root of 100-x^2

10.) f(x) = square root of x^2-5x+6

11.) f(x) = 9x-1/square root of x^2-5x+6

Below are the answers I got (not sure if they're correct!):

1. (-infinity, 7/11) U (7/11, infinity)

2. (-infinity, -3) U (-3, -1) U (-1, infinity)

3. (-infinity, infinity)

4. (-infinity, 5/2]

5. (-infinity, infinity)

6. (4, infinity)

7. (-infinity, infinity)

8. (-infinity, -9) U (9, infinity)

9. Wasn't sure how to answer this one!

10. (-infinity, 2) U (3, infinity)

11. (-infinity, 2) U (3, infinity)

Thank you in advance!