A(1,2,k) lies on the plane x + 2y - 2z = 8. Find:

a) the value of k.

b) the coordinates of B such that AB is normal to the plane and 6 units from it.

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- October 9th 2010, 10:43 AMxXLeetayXxLines and Planes Help!
A(1,2,k) lies on the plane x + 2y - 2z = 8. Find:

a) the value of k.

b) the coordinates of B such that AB is normal to the plane and 6 units from it. - October 9th 2010, 10:58 AMEvaldas
Well a) according to me would be (assuming in the place of k there should the z axis coordinate, so then z=k) 1 + 2*2 - 2z = 8 => 1 + 4 - 2z = 8 => 2z = 5 - 8 => 2z = -3 /:2 => z = -1.5

- October 9th 2010, 11:41 AMPlato
The part b) is a good bit more difficult.

We need to find a value of so that

Note there are two such points for .