What is the inverse of the function f(x)= 1/4x - 12?

Answer question above and explain each step : )

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

40 points which is the equation of a line perpendicular to the line with the equation: y = 1/4x + 2 a : y = -4x - 7 b : y = 4x + 2 c : y = 1/4x - 1/2 d : y = -1/4x + 3