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Inverse functions

  • Thread starter Ry122
  • Start date
  • #1
565
2
how do i find
f(x)^-1 of y=4x+9/2x-3
the answer in the back of the text book is

f(x)^-1=3x+9/2x-4
 

Answers and Replies

  • #2
529
1
Show your attempt at a solution, or pay me 1 dollar for doing your homework for you (your choice).
 
  • #3
565
2
2x=4x+9/y + 3y/y
2x=4x+9+3y/y
How do i move 4x to the other side?
 
  • #4
529
1
is 9/2x in your original post 9/(2x)? Just want to check.
 
  • #5
565
2
Heres the full working out:
y(2x-3)=4x+9
2x-3=4x+9/y
2x=4x+9/y + 3
2x=4x+9/y + 3y/y
 
  • #6
529
1
You gotta learn to put brackets in your eqns. There's no way anyone could have understood your original problem without the brackets.

y(2x-3)=4x+9
x(2y-4)-3y=9
x=(9+3y)/(2y-4)
 
  • #7
565
2
Sorry to bother u again but how
do u get from
y(2x-3)=4x+9 to
x(2y-4)-3y=9
 
  • #8
529
1
expand and collect terms in x

y(2x-3)=4x+9
->
y2x-3y=4x+9
->
x(2y)-3y=x(4)+9
->
x(2y-4)-3y=9
 

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