## sarahc 2 years ago Let f(x) = 5x + 12. Find f–1(x).

1. LordVictorius

I was also confused on these.

2. LordVictorius

Switch y and x, y being f(x)

3. mathsmind

is this question about finding the inverse of a function?

4. LordVictorius

Yes.

5. LordVictorius

f-1(x)

6. LordVictorius

f^-1

7. mathsmind

$y = 5x +12$

8. LordVictorius

Yes.

9. LordVictorius

x=5y+12

10. mathsmind

$x = 5y +12$

11. LordVictorius

Solve for x.

12. LordVictorius

lol

13. LordVictorius

x-12=5y

14. LordVictorius

(x-12)/5=y

15. mathsmind

$5y = x -12$

16. mathsmind

$y = \frac{ x-12 }{ 5 }\rightarrow f ^{-1}(x)=\frac{ x }{ 5 }-\frac{ 12 }{5 }$

17. LordVictorius

Too late, I got it.

18. LordVictorius

I GTG.

19. LordVictorius

Good luck math.

20. mathsmind

$y = \frac{ 1 }{ 5 }(x-12)$

21. sarahc

so it would x-12/5?

22. mathsmind

yup

23. sarahc

thanks!

24. mathsmind

you are welcome but follow the steps

25. mathsmind

so you can do it yourself

26. mathsmind

if you practice the steps i showed you, you'll almost be able to solve any problem of the kind

27. sarahc

okay I did. I got 100 :)

28. LordVictorius

Good for you.

29. mathsmind

did u get 100%

30. mathsmind

good i am happy

31. LordVictorius

Thanks.

32. mathsmind

sorry i was busy in the computer science section

33. LordVictorius

lol

34. LordVictorius

Anyway, can you help me?

35. LordVictorius

I posted my questions.

36. mathsmind

sure what is ur qs? if i know how to solve it?

37. LordVictorius

Bumping now.

38. mathsmind

so where is the question

39. LordVictorius

It should be the third one down.