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 the two vectors are collinear or orthogonal; e) check whether the three vectors are coplanar. a (2; -7; 5); b (-1; 2; -6); c (3; 2; -4).

No. 2 The tops of the pyramid are at points A (5; 2; 7); B (7; –6; –9); C (–7; –6; 3); D (1; –5; 2) ...

No. 3 Given three forces P (4; –2; –5); Q (5; 1; –3); R (–6; 2; 5); applied to point A (–3; 2; –6). Calculate a) the work produced by the resultant of these forces; when the point of its application, moving rectilinearly, moves to point B (4; 5; –3); b) the value
the moment of the resultant of these forces with respect to point B.