" (面) "2x^(2)+z-6=0

If plane 2x+3y+6z+k=0 is tangent to the sphere x^(2)+y^(2)+z^(2)+2x-2y+2z-6=0 , then a value of k is

The equation of the parallel plane lying midway between the parallel planes 2x-3y+6z-7=0 and 2x-3y+6z+7=0 is (A) 2x-3y+6z+1=0 (B) 2x-3y+6z-1=0 (C) 2x-3y+6z=0 (D) none of these

The equation of the parallel plane lying midway between the parallel planes 2x-3y+6z-7=0 and 2x-3y+6z+7=0 is (A) 2x-3y+6z+1=0 (B) 2x-3y+6z-1=0 (C) 2x-3y+6z=0 (D) none of these

Solve for z : z^(2) - 6z + 6 = 0 .

If plane 2x+3y+6z+k=0 is tangent to the sphere x^(2)+y^(2)+z^(2)+2x-2y+2z-6=0 , then a value of k is (a) 26 (b) 16 (c) -26 (d) none of these

Equation of the acute angular bisector of the planes 2x-y-2z-6=0,3x+2y-6z-12=0 is