Communication [13 marks] True/False Indicate whether the statement is true or false. 9. A normal vector to a line is perpendicular to that line. 10. There is no symmetric form for the equation of a plane. 11. The direction vector of a line is an indicator of its slope. 12. There is no scalar equation of a line in three space. 13. A plane written in scalar form cannot be written in vector form. 14. Any three non-collinear points in space will define a unique plane. 15. In three-space there are four possibilities for the intersection of two lines. 16. A line will always intersect with a plane. Completion Complete each statement. 17. Two planes are parallel if their normals are 18. If three planes intersect in a point then the triple scalar product of their normal zero. 19. In three-space, if two lines are not parallel and do not intersect, they are called 20. If the dot product of the direction vector of a line and the normal of a plane is not equal to zero, then the intersection of the line and the plane is a 21. If the normals of two planes are not collinear, then the planes will always intersect in a