Find a vector equation and parametric equations for the line segment that joins P to Q. P(1,-1,8), Q18, 2, 1) vector equation r(t) = (1 - 7t, 3t - 1,8 - 7t) x parametric equations (x(1), y(t), 2(0) - 1 - 71,3 1,8 - 71 )