Hello, Jenny,

your equation is given in normal form. The normal vector which is perpendicular to the palne is: <3, -4, 1>.

The given vector is 3*<3, -4, 1> = <9, -12, 3> thus this vector is perpendicula to the plane too.

Plug in the coordinates of the point:

3*0-4*0+1-1=0 which is true. Thus the point belongs to the plane.

EB