Question

Given the function f(x) = 4(x+3) − 5, solve for the inverse function when x = 3

Answer 1

`f(x)=4(x+3)-5\\ y=4(x+3)-5\\ y=4x+12-5\\ y=4x+7\\ 4x=y-7\\ x=(1)/(4)y-(7)/(4)\\ f^(-1)(x)=(1)/(4)x-(7)/(4)\\ f^(-1)(3)=(1)/(4)\cdot3-(7)/(4)\\ f^(-1)(3)=(3)/(4)-(7)/(4)\\ f^(-1)(3)=-(4)/(4)\\ f^(-1)(3)=-1`

Answer 2

f(X)=4x+12-5=4x+7
so
{f(x)-7}/4=x
now in inverse func. f(x0 is converted into x and x is converted into
f(x)^-1
so
f(x)^-1=[x-7]/4
now if x=3
f(3)^-1=[3-7]/4=-4/4=-1