Number 1 are given the vector. It is necessary: ​​a) to calculate the mixed product of three vectors; b) find the module of the vector product; c) calculate the scalar product of two vectors; d) check whether two vectors are collinear or orthogonal; e) check whether the three vectors are coplanar. a (-9; 4; -5); b (1; -2; 4); c (-5; 10; -20)

No. 2 The tops of the pyramid are located at points A (7; –1; –2); B (1; 7; 8); C (3; 7; 9); D (–3; –5; 2) ...

No. 3 Given three forces P (3; –4; 2); Q (2; 3; –5); R (–3; –2; 4); applied to point A (5; 3; –7). Calculate a) the work produced by the resultant of these forces; when the point of its application, moving rectilinearly, moves to point B (4; –1; –4); b) the value
the moment of the resultant of these forces with respect to point B.