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 (4; 2; -3); b (2; 0; 1); c (-12; -6; 9)

No. 2 The tops of the pyramid are at points A (7; 5; 8); B (–4; –5; 3); C (2; –3; 5); D (5; 1; –4) ...

No. 3 Force F (–9; 5; 7) is applied to point A (1; 6; –3). Calculate a) the work of force in the case; when is the point of her application; moving rectilinearly moves to point B (4; –3; 5); b) the modulus of the moment of force with respect to point B.