**earlier problem**.

Can you find all possible

*non zero real quadruplet(s)*

**(P, Q, R, S)**that satisfy the following system of

*simultaneous equations*?

**2*Q = P + 19/P,**

*and*:

**2*R = Q + 19/Q,**

*and*:

**2*S = R + 19/R,**

*and*:

**2*P = S + 19/S.**

__Bonus Question__:

In the problem given above, if the number

**19**was replaced throughout by a

*real constant*

**M > 1**, what would have been the possible non zero real quadruplet(s)

**(P, Q, R, S)**that satisfy the given set of equations,

*in terms of*

**M**?