Question: A firm's total expenditure E on inputs is determined by the formula
E = PKK + PLL
where K is the amount of input K used, L is the amount of input L used, PK is the price per unit of K and PL is the price per unit of L. Is one unique value for E determined by any given set of values for K, L, PK and PL? Does this mean that any one particular value for E must always correspond to the same set of values for K, L, PK and PL?