f (x) stuff again?

Question

if f(x) =5x+7 find f^-1^ (2)

is it
2-7/5
= 5/5
=1

Answer 1

f(x) = y = 5x +7

now get x in terms of y

5x = y-7
x = (y-7)/5

so f^-(x) = (x-7)/5

so f^-(2) = (2-7)/5 = 5/5 = 1

so your step is right

Answer 2

To find f^-1(x), set y = f(x): y = 5x+7
Switch x and y: x = 5y+7
Solve for y: (x-7)/5 = y
So f^-1(x) = (x-7)/5
And f^-1(2) =(2-7)/5=-5/5=-1

Answer 3

I take it you want the inverse function (given f(x) is 2, find x). The answer is (2-7)/5

Answer 4

if u want a detailed expression,here goes:

let f(x)=y
therefore y=5x+7
y-7=5x
x=(y-7)/5
f^-1(y)=x (inverse y u get x)
f^-1(y)=(y-7)/5
f^-1(x)=(x-7)/5 (substitute x with y )
f^-1(2)=(2-7)/5
therefore u get -1 as your ans.