I am having some trouble with these questions. Thank you so much in advance

Find the points of intersection for the lines r(t) = <2t, 1-2t, 3> and w(s) = if possible. If there is no intersection, explain why.

Find the points of intersection for the plane 4x+6y-2z = 3, and the line r(t) = <2, 3-t, 3t+1>

Find the critical points for f(x,y) =x2y+x2+y2