-
: , ,
()_ (. .) 7_ XVII
6 ( , )
. XIX : -. , ; .
XX :
XX
: .
XIX - XX
, ? - . , . . , , , ,
a = (1; 2; 3), b = (61; 62; 63), c = (c1; C2; C3), d = d2; d3) . , a, b, c ­ d . a = (-2; 4; 1), b = (1; 7; -8), c = (-3; -2; 5), d = (-4
XIX
XVI
. 20 .