Thought it possible to simplify in order to be able to write the solutions of the equation. For this we use the decomposition of the number $c$ on the multipliers.
To record decisions have to know first the solution of the Pell equation $(Z_1;R_1)$.
And solving the following equation Pell $(k_0;n_0)$.
Then the formula is as follows.
The problem in finding the first solution for General Pell equation $(Z_1;R_1)$.
The meaning of the solution is that to factor the number. $c=ab$
Then degradable factoring the difference. $xy=a-b$
If the following expression may be a square.
Then the first solution is written simply.
Such record these formulas will greatly simplify the calculations. Always better to have a formula.