Question

If $y=f\left(x\right)=\frac{5x+3}{4x-5}$ then $f\left(y\right)$

• A. $-x$
• B. $x$
• C. $\frac{5y+3}{4y-5}$
• D. $2x$

Answer 1

Answer: (C)

$\frac{5y+3}{4y-5}$

$y=f\left(x\right)=\frac{5x+3}{4x-5}$

$4xy-5y=5x+3$

$4xy-5x=5y+3$

$x(4y-5)=5y+3$

$x=\frac{5y+3}{4y-5}=f\left(y\right)$.