Find all the points on the surface x 2 + 9 y 2 + 4 z 2 = 17 {\displaystyle \displaystyle x^{2}+9y^{2}+4z^{2}=17} where the tangent plane is parallel to the plane x − 8 z = 0 {\displaystyle \displaystyle x-8z=0} .
