Step by step, starting from the very beginning:


    4P + (1-P)*5.78 = 5


    4P + 5.78 - 5.78P = 5


Collect all the terms with P on the right side.
Collect all the constant terms on the left side.


So, you will move the terms from one side to another.


EACH TIME  when you move the terms from one side to another, CHANGE their signs:


    5.78 - 5 = 5.78P - 4P.


    0.78 = 1.78P


Divide both sides by the coefficient  1.78 at P:


    P =  = 0.438   is your answer.