For the function f(x)=1/3x+1, find the value of x for which f(x)=x

I know how to solve this equation if say, the question was:

f(5)=1/3x+1, solve when f(5), (1/3)*5+1->5/3+1->8/3 (or 2 and 2/3)

but the portion of the question "find the value of x for which f(x)=x" doesn't make any sense to me.

Could anyone help me out?

The questions wants you to find a value for x where the y value would be equal that x value, or f(x) = x.
Just set f(x) = x
f(x)=1/3x+1
then x = 1/3x +1
x-1/3x = 1
2/3x = 1
2x = 3
x = 3/2

x = x/3+1
3x = x + 3
2x = 3
x = 3/2