## anonymous one year ago .

1. anonymous

@triciaal can you help me. You and I are the only ones online I think lol.

2. anonymous

the inverse of multiplication is division and for addition is subtraction

3. anonymous

okay

4. anonymous

so, the inverse of 1/4x=4x

5. anonymous

example the inverse of 6x= 1/6x

6. anonymous

please answer this for me . what is the inverse of 100x?

7. anonymous

so then it has to be f^-1(x) = 4x - 3

8. anonymous

x/100 ?

9. anonymous

nooo. the anser is 1/100x

10. anonymous

another question. what is the inverse of 20x?

11. anonymous

1/20x I'm confused. I hate this

12. anonymous

thats is right

13. anonymous

okay

14. anonymous

what is the inverse of 15?

15. anonymous

-15?

16. anonymous

just from what you've told me I actually think it's f^-1(x) = 4x - 3 and not the first answer I had. My packet isn't doing a very good job of explaining this.

17. anonymous

very correct

18. anonymous

I guess I thought that the x should be in the parenthesis with the 3 but now I know that was super wrong. So thank you :)

19. anonymous

Also I need to find better explanations of this, my packet does a sucky job.

20. anonymous

ok

21. anonymous

thanks again tho

22. anonymous

Here are simple steps for inverse: Replace f(x) with y Switch x's and y's, so put x where y is and x where y is. Solve for y Replace y with f^-1(x)

23. anonymous

@iambatman thank you :)

24. anonymous

Yw :)

25. anonymous

are you here?

26. amilapsn

yeah

27. anonymous

okay

28. amilapsn

So the original expression will be: $$y=\frac{1}{4}x+3$$ ok?

29. anonymous

right

30. amilapsn

Can you guess what switching $$x$$ and $$y$$ means?

31. anonymous

okay so switching them I thought meant doing 1/4x= y+3

32. anonymous

that's where I wasn't sure what I was doing.

33. amilapsn

No that guess was wrong.. ;)

34. amilapsn

Switching means simply interchanging... For example: Before switching: $$\color{blue}y=2\color{red}{x}+1$$ After switching: $$\color{red}{x}=2\color{blue}y+1$$ ok?

35. anonymous

yeah okay so the 1/4 would just stay where it was initially.

36. amilapsn

exactly! So now what the answer would be?

37. anonymous

it would be f^-1(x)= 4x-3?

38. amilapsn

no... Not quite. after switching what would you get?

39. anonymous

okay so the problem would look like x=1/4y+3 the inverse of addition is subtraction (like said above)

40. anonymous

f^-1(x) = 4(x-3)

41. anonymous

iambatman said to solve for y how would I do that?

42. amilapsn

that's right!

43. anonymous

44. anonymous

@GIL.ojei did we do it wrong the first time around? Would you say that it's right this time?

45. amilapsn

yep.. BTW solving for y means expressing y in terms of x. that means you've got $$x=\frac{1}{4}y+3$$ after switching.. After solving for $$y$$ means just getting $$y=4(x-3)$$

46. amilapsn

ok?@GIL.ojei

47. anonymous

@lily1021 IS Y=4X-12 OR 4(X-3) IN YOUR OPTION?

48. anonymous

yep those were both in my options which why I was torn between them. I didn't know what made them different.

49. anonymous

oh wait I missed the 12 in your post. No y=4x-12 is not in my options but 4(x-3) is

50. anonymous

OK . GO WITH THAT .

51. anonymous

okay thank you. and big thanks to @amilapsn for coming back and helping me through this. It means so much to me you have no idea lol :)

52. amilapsn

YX @lily1021 lol :D

53. anonymous

I have another similar one I have to solve but I think it would kinda be the same. Can I post so you can check? I'll do it in a new post so I can medal you.