Given 4f (x) + 3f (1 / x) = x, find the analytic expression of F (x)

Given 4f (x) + 3f (1 / x) = x, find the analytic expression of F (x)

4f(x)+3f(1/x)=x ①
Let x = 1 / X
4f(1/x)+3f(x)=1/x ②
②*3/4
3f(1/x)+9f(x)/4=3/4x ③
①-③
9f(x)/4-4f(x)=3/4x -x
f(x)=4x/7- 3/7x