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

Question 882022: If , show that
Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website!
, show that

Sorry but that is just not true in general.  

Here is a disproof by a counterexample.

If it were true in general it would be true if x = 1

Suppose x = 1











Now in order for what we are asked to prove to be true in this
case, we must end up with

, which in this case would be



However f(-2) is found by substituting x=-2 in











which is false.  So what you were asked to
prove is not true.

Edwin

RELATED QUESTIONS
If y=f(x) = 3x + 7 / 4x - 9 , show that x = f(y)... (answered by josgarithmetic)

If {{{f(x,y) = x^4 + 3x^2y^2 + y^4 }}} , show that {{{f(ax,ay) =... (answered by Fombitz)

y=f(x)=-4x (answered by Fombitz)

if f(x+y)=f(x)+f(y) and f(1)=5 then... (answered by Fombitz)

1) Let f(t)=(t^2+6t+4)(2t^2+5) f'(t)= f'(2)= 2) f(x)=4x / √8x2+5x−5. (answered by solver91311)

If f(x) = x^2+3x-7 and g(x)= 2x^3-4x+9, find... (answered by robertb)

2) Determine whether the function rule models discrete or continuous data. A produce... (answered by jim_thompson5910)

if f(x)=2x show that f (x + 4)-f(x-2)=63/4 if f(x,y) = x4 + 3x2 y2 + y4 show that f (answered by jim_thompson5910)

solve it if y = 0 f(x) : 3x^2 - 4x / x+1 = -ln... (answered by Fombitz)