If f : R → R such that f(x)=5x+4 then which of the following is equal to f^{1}(x).

×
\dfrac{x5}{4}

✓
\dfrac{x4}{5}

×
\dfrac{x+4}{5}

×
\dfrac{x}{5} 4
If f : R → R such that f(x)=5x+4 then which of the following is equal to f^{1}(x).
\dfrac{x5}{4}
\dfrac{x4}{5}
\dfrac{x+4}{5}
\dfrac{x}{5} 4
Let y=5x+4
Express x in terms of y
x=\dfrac{y4}{5}
Therefore, its inverse function is
f^{1}(x)=\dfrac{x4}{5}