var x = Quadratic(3, 4, 5) # represents: 3 + 4*sqrt(5)
var y = Quadratic(6, 1, 2) # represents: 6 + sqrt(2)
say x**10 #=> Quadratic(29578174649, 13203129720, 5)
say y**10 #=> Quadratic(253025888, 176008128, 2)
say x.powmod(100, 97) #=> Quadratic(83, 42, 5)
say y.powmod(100, 97) #=> Quadratic(83, 39, 2)