How to describe a line in given a direction vector & point in parametric equations & vector-form. How to describe a line in given an orthogonal vector & point in parametric equations & vector- form. Solve for x & then substitute t, for y to get parametric equations. How to describe a plane in given an orthogonal vector & point in parametric equations & vector- form. Pick arbitrary point on line & create vector since vector normal to line, Solve for x & substitute t, for y & s, for z to get parametric equations. From parametric equations, coefficients of t & s become direction vectors & constants become point on line (should be same as given point), then follow procedure for writing equation in vector-form given a point & direction vectors. How to describe a line in given 2 points.