If there are four equations and only three variables, and no one of the equations is derivable from the others by algebraic manipulation then there is another variable missing.
Quotes about derivable (3 Quotes)
The human being who lives only for himself finally reaps nothing but unhappiness. Selfishness corrodes. Unselfishness ennobles, satisfies. Don't put off the joy derivable from doing helpful, kindly things for others.
THERE are three types of approaches towards the Lord the Eagle type, which swoops down on the target with a greedy swiftness and suddenness which, by its very impact, fails to secure the object coveted the Monkey type, which flits hither and thither, from one to another, unable to decide which is tasty and the Ant type which moves steadily, though slowly towards the object which it has decided is desirable. The ant does not hit the fruit hard and makes it fall away it does not pluck all the fruits it seeks it appropriates just as much as it can assimilate and no more. Do not fritter away the time allotted to you for sojourning on the earth in foolish foppery and fanciful foibles, which always keep you outdoors. When are you to walk indoors into the warmth and quiet of your own interior Retire into solitude and silence now and then experience the joy derivable only from them.