30. 1 point if the plane 2x-2y +z= 9 touches the x* + y +z' =r', the value of r is (b) 2 (a) 1 (d)9 (c) 3 o a o b o od 3.* 1 point the sum of the squares of the

30. 1 point If the plane 2x-2y +z= 9 touches the x* + y +z' =r', the value of r is (b) 2 (a) 1 (d)9 (C) 3 O a O b O Od 3.* 1 point The sum of the squares of the direction cosines of any line is always (b) 5 (d) )2