Show that the parametric equations x x1 x2 - x1t y y1

Question

(a) Show that 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).

(b) Find parametric equations to represent the line segment from (-2, 9) to (1, -1). (Enter your answer as a comma-separated list of equations. Let x and y be in terms of t.)