# Find the value of function f(5/4)

#### Sandeep Kumar

Could someone, please, help me solve this?

Let f be a function with the domain the set of all real numbers except 0 and 1 ,that satifies the equation :

2xf(x) - f[(x-1)/x] = 20

Find f(5/4)

#### joshuaa

try to use

f(x) = 1/x + 1/(x - 1)

#### Idea

Let

$$\displaystyle g(x)=2x f(x)-f\left(\frac{x-1}{x}\right)$$

and solve the system

$$\displaystyle g\left(\frac{5}{4}\right)=20,g\left(\frac{1}{5}\right)=20,g(-4)=20$$

topsquark

#### Sandeep Kumar

I've actually solved this right after posting it. How can I delete this post? I tried to unwatch it. It's not working.

f(5/4) = 68/3

f(1/5) = 110/3

f(-4) = -16/3

#### topsquark

Forum Staff
I've actually solved this right after posting it. How can I delete this post? I tried to unwatch it. It's not working.
MHF policy is to not delete threads or posts unless there is a serious situation. I'm going to leave this. Someone else might get something out of it as well.

-Dan