In higher mathematics, how to find the normal vector of a plane equation?

In higher mathematics, how to find the normal vector of a plane equation?

In the space coordinate system, the plane equation can be used as the cubic equation
The general equation AX + by + CZ + D = 0
So its normal vector is (a, B, c)
You can see from the point formula of the plane:
n·MM'=0,n=(A,B,C),MM'=(x-x0,y-y0,z-z0)
A(x-x0)+B(y-y0)+C(z-z0)=0
Finding the plane of three points can orient the product as normal
The graph of any cubic equation is always a plane, where the coefficients of X, y and Z are the coordinates of a normal vector of the plane