Question

If f(x) = 3x + 5, then what is f–1(x) ?

Answer 1

y = 3x+5, solve for x

Answer 2

or, since the inverse of (x,y) is (y,x)

we can swap our a and y positions:

x = 3y+5; and solve for "y" to get f-1(x)

Answer 3

our x and y positions ... i need a few more keys to keep track of

Answer 4

soo what 5-1(3)?

Answer 5

let y=f(x)..
then y= 3x+5;
=> (y-5)/3=x; ----(eq.1)
=> as y=f(x);
=> x=f-1(y);
so from eq.1 (y-5)/3=f-1(y); -------(eq.2)
=> replace 'y' with 'x' in eq.2
then (x-5)/3= f-1(x) ----ans.

thus f-1(x)=(x-5)/3
this is generalized one...u need to knw the domain and interval to restrict the limit.

Answer 6

5-1(3) ..... not quite

x = 3y+5
-5 -5
---------
x-5 = 3y


and then finish off by dividing off that 3