Thanks to Vin, I proceed as follow:

• make a guess f (0.1 for instance)
• get v from here (4th eq)
• get Re and from here (2nd eq)
• get a new f (eq3) using bissection method for instance
• Continue as long as f varies a lot (at some point it converges)

It is easy to program with a while loop and a stopper based difference between f_init and new_f

f=0.1 -> v=0.487 m/s -> Re=58522 -> f=0.02 -> v=1.09m/s -> Re=130861 -> f=0.017 -> v=1.1.18 -> Re=141938 and this is the final solution given in the book