If xy+z=x(y+z),which of the following must be true?
1) x=0 and z=0
2)x=1 and y=1
3)y=1 and z=0
4)x=1 or y=0
5)x=1 or z=0
1) x=0 and z=0
2)x=1 and y=1
3)y=1 and z=0
4)x=1 or y=0
5)x=1 or z=0
xy+z=xy+xz
Z=XZ
Z(1-x)=0
so either z =0 or x =1
