SOLUTION: If y=f(x) = 3x + 7 / 4x - 9 , show that x = f(y) Thanks.

Algebra ->  Functions -> SOLUTION: If y=f(x) = 3x + 7 / 4x - 9 , show that x = f(y) Thanks.      Log On


   

Question 881820: If y=f(x) = 3x + 7 / 4x - 9 , show that x = f(y)
Thanks.
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
You are expecting that the function as its own input will be x?



Multiply top and bottom by 4x-9



%283%283x%2B7%29%2B7%284x-9%29%29%2F%284%283x%2B7%29-9%284x-9%29%29

%289x%2B21%2B28x-63%29%2F%2812x%2B28-36x%2B81%29

%2837x-42%29%2F%28-24x%2B109%29

NO! That is not x.


Did you really intend the term, 7%2F4x in the original function definition?