1. anonymous

z-4=$z-4\frac{ y ^{2}+8z-48}{ z-4 }$

2. anonymous

3. anonymous

@kohai please can you help me??

4. DanJS

you get anyqwhere?

5. anonymous

6. anonymous

is it going to be y=z-4?

7. DanJS

you need to isolate y on one side and it will = something in terms of all the other stuff, x

8. DanJS

I would multiply both sides of the thing by (z-4) first

9. anonymous

10. DanJS

should that be a +8y instead of the +8z you typed?

11. anonymous

its a multiple choice question is my answer right?

12. DanJS

|dw:1443160932457:dw|

13. anonymous

its 8z

14. DanJS

ok, just checking, that makes it easier, asking because a y would be a factorable numorator.

15. DanJS

multiply both sides by (z-4) (z - 4)*(z-4) = y^2 + 8z - 48

16. DanJS

expand z^2 - 8z + 16 = y^2 + 8z - 48

17. anonymous

$y=\sqrt{z ^{2}+6z-40}$

18. DanJS

move the 8z and the -48 to the other side... z^2 - 16z + 64 = y^2

19. DanJS

take the root of both sides, and you get two answers for y, the + and the - root of all that on the left

20. DanJS

$y = \pm \sqrt{z^2-16z+64}$

21. DanJS

looking closer, the stuff under the root is a perfect square, factors to (z-8)^2 so you get simplified y = z - 8 or y = -(z-8)

22. anonymous

so thats the answer? because i said y=z-8

23. anonymous

@DanJS

24. DanJS

sorry, back

25. DanJS

yeah if that is the only choice in the multiple choice , there is also the negative of that , and there is a restriction on the values of z, but not sur eif you need that