Question

dada a função f (x) dada por f(x) = 3x-27 calcule f^-1 (3)

Answer 1

Vamos obter a inversa da função

$\mathsf{y=3x-27}\\\mathsf{3x=y+27}\\\mathsf{x=\dfrac{y+27}{3}}\\\mathsf{{f}^{-1}(x)=\dfrac{x+27}{3}}$

substituindo x por 3 temos

$\mathsf{{f}^{-1}(3)=\dfrac{3+27}{3}=\dfrac{30}{3}}\\\huge\boxed{\boxed{\mathsf{{f}^{-1}(3)=10}}}$