The question is:

If the positive z-axis points upward, an equation for a horizontal plane through the point (-3,-2,4) is:

An equation for the plane perpendicular to the x-axis and passing through the point (-3,-2,4) is:

An equation for the plane parallel to the xz-plane and passing through the point (-3,-2,4) is:

I have a test on this TUESDAY, and any help with these would be greatly appreciated.