No. 1 Given four points A1 (2; 1; 7); A2 (3; 3; 6); A3 (2; –3; 9); A4 (1; 2; 5). Draw up the equations: a) plane A1A2A3; b) straight line A1A2; c) a straight line A4M perpendicular to the plane A1A2A3; d) line A3N parallel to line A1A2; d) a plane passing through point A4, perpendicular to the line A1A2. Calculate: e) the sine of the angle between the straight line A1A4 and the plane A1A2A3; g) the cosine of the angle between the Ohu coordinate plane and the A1A2A3 plane.

No. 2 Make the equation of the plane passing through the origin perpendicular to the planes x + 5y - z + 7 = 0 and
3x - y + 2z - 3 = 0.

№3 Make an equation of a line passing through point M (2; 3; 1) perpendicular to the line .....