Mark M. answered 09/26/23
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
r(t) = t<3, -4, -8> + <0, 5, 1>
w = <3, -4, -8> is parallel to the plane and v = <0-1, 5-2, 1-3> = <-1, 3, -2> is also parallel to the plane.
v x w is perpendicular to the plane.
v x w = <32, 14, 5>
Let (x, y, z) be an arbitrary point on the plane. So, <x - 1, y - 2, z - 3> is parallel to the plane.
<32, 14, 5> • <x - 1, y - 2, z - 3> = 0
32(x - 1) + 14(y - 2) + 5(z - 3) = 0
32x + 14y + 5z = 75