Question

Se a função f(x) = (5x − 1)/2 e f−1(x) = (2x + 1)/m, o valor de m é:

A) 3
B) 5
C) 2
D) 4
E) 1

Answer 1

$\Large\boxed{\begin{array}{l}\sf f(x)=\dfrac{5x-1}{2}\\\sf 5x-1=2f(x)\\\sf 5x=2f(x)+1\\\sf x=\dfrac{2f(x)+1}{5}\\\\\sf f^{-1}(x)=\dfrac{2x+1}{5}\\\\\sf f^{-1}(x)=f^{-1}(x)\\\sf\dfrac{2x+1}{m}=\dfrac{2x+1}{5}\\\\\sf m=5\\\huge\boxed{\boxed{\boxed{\boxed{\sf\red{\maltese}~\blue{alternativa~B}}}}}\end{array}}$