Question

AJUDA NESSA PERGUNTA !
Dada a função f(x)=3x-m/4.se f^-1(5)=2,determine o valor de m.

Answer 1

           $f(x) = y \\ \\ y=3x- \frac{m}{4} \\ \\ 4y=12x-m \\ \\ 4y+m=12x \\ \\ x= \frac{4}{12} y+ \frac{m}{12} \\ \\ x= \frac{y}{3} + \frac{m}{12} \\ \\ y^{-1} = \frac{x}{3} + \frac{m}{12}$

           $f^{-1} (5)=2= \frac{5}{3} + \frac{m}{12} \\ \\ 2.12=5.4+m \\ \\ 24-20=m \\ \\ m=4$