Вариант 21 ИДЗ 1.1

DHS - 1.1
№ 1.21. For this determinant find the minors and algebraic additions.
Calculate the determinant: a) spreading it over the elements i of the string; b) spreading it into j column elements; c) having previously received zeros in the i line. i = 1; j = 2.
No. 2.21. Two matrices A and B are given. Find: a) AB; b) BA; c) A – 1; d) AA – 1; e) A – 1A.