Point of intersection inside 3D triangle?

Lets say I have a triangle with V1(x,y,z), V2(x,y,z) and V3(x,y,z) and a point P(x,y) inside the triangle. How can I compute for P(z) if values of V1, V2, V3 and P(x,y) are known?

I’m not good in math, please help.

Thanks!

okay I got it, its Ax + By + Cz = D

thanks anyway…