 Hilbert's tenth problem was to find a general algorithm which can decide whether a given Diophantine equation has a solution among the integers.While Hilbert's tenth problem is not a formal mathematical statement as such, the nearly universal acceptance of the (philosophical) identification of a decision algorithm with a total computable predicate allows us to use the MRDP theorem to conclude that the tenth problem is unsolvable.The Pell equation

is an example of a Diophantine equation with a parameter.