The parametric equations x = x1 + (x2 − x1)t, y = y1 + (y2 − y1)t where 0 ≤ t ≤ 1 describe the line segment that joins the points p1(x1, y1) and p2(x2, y2). use a graphing device to draw the triangle with vertices a(1, 1), b(5, 3), c(1, 6). find the parametrization, including endpoints, and sketch to check. (enter your answers as a comma-separated list of equations. let x and y be in terms of t.)