Question

УМОЛЯЮ!!!!!!!!!!!!!!!

Answer 1

Ответ:

9. a*b = |a|*|b|*cos60 = 12/2 = 6;

10. AB(-3; -1); AC(-1; -7)

AB*AC = (-3)*(-1) + (-1)*(-7) = 10;

11. S = 1/2 * sin45 * 4 * 6 = 6$\sqrt{2}$