## WiseOlMoosey 2 years ago How would I find the domain and range of (2)/(x^2-2x-3)? Is the domain x=-1 x=3

1. cwrw238

try factoring the denominator what values of x are not possible?

2. WiseOlMoosey

x=-1 and x=3

3. cwrw238

the domain is all possible values of x

4. cwrw238

right

5. cwrw238

so -1 and 3 are not in the domain

6. mathstudent55

The domain is the values that x can have. y = 2/(x^2 - 2x - 3) has a denominator. Since division by zero is not allowed, you need to find which values of x would make the denominator zero. To do that, solve (which you did) x^2 - 2x - 3 = 0 (x - 3)(x + 1) = 0 x = 3 or x = -1 These are the value of x that must be excluded from the domain, so the domain is all real numbers except x = 3 and x = -1.

7. WiseOlMoosey

oh so all reals except x=-1 and x=3 for the domain

8. cwrw238

yup

9. WiseOlMoosey

ok thanks! but what about the range?

10. cwrw238

the range is all possible values of f(x)

11. cwrw238

so can you figure that out?

12. WiseOlMoosey

um how would i set it up?

13. WiseOlMoosey

dang ok.. don't solve it for me but how would i go about that?

14. cwrw238

well for a start the values of f(x) corresponding to x=3 or -1 will be excluded

15. WiseOlMoosey

Couldn't I find the inverse of the function and then find the domain?

16. WiseOlMoosey

@cwrw238

17. cwrw238

yes the inverse of the function has domain which equals range of the function

18. WiseOlMoosey

ok thanks for your time and patience!

19. cwrw238

yw