Question

1)  (x-2y+z) (x-2y-z)=
2) (a-b+c) (a+b+c)=
3) (x+y+z) (x+y-z) (x-y+z) (x-y-z)=
4) (x  +2)?=
    2
resolver con mas su operacion..

Answer 1

la 2 sale  2ac+a2+c2-b2