## anonymous one year ago For what value of x is the rational expression below undefined? 2x+4/x-7 A. 2 B. -2 C. -7 D. 7

1. kc_kennylau

$\Large f(x)=\frac{2x+4}{x-7}$

2. kc_kennylau

So, we can't divide by zero, right?

3. anonymous

i believe so

4. anonymous

its undefined so that s what got to me

5. kc_kennylau

What value of $$\Large x$$ would cause this problem?

6. anonymous

so would i just plus it all in?

7. kc_kennylau

Well that's one way of solving the puzzle, you can do that

8. UsukiDoll

what values of x makes the fraction undefined?

9. anonymous

but how would i know which one is undefined?

10. UsukiDoll

waitttt! look at the denominator first

11. anonymous

and hi miku hahaha

12. UsukiDoll

focus on that denominator just that denominator

13. UsukiDoll

we have x -7 right ?

14. anonymous

7?

15. anonymous

-7 yea

16. anonymous

wouldn't it have to be positive to be a undefined?

17. UsukiDoll

whoa... x - 7 what value of x makes it 0? it's like x-7 = 0 solve for x

18. UsukiDoll

yeah it has to be positive to be undefined

19. UsukiDoll

if you have a fraction like 1/0 that's undefined...we can't divide by 0

20. anonymous

ok thanks :)

21. anonymous

i got it well i understand it haha