xyz  F1 F1' F2 F2'
000  1  0   1  0
001  0  1   1  0
010  1  0   1  0
011  0  1   1  0
100  0  1   0  1
101  0  1   0  1
110  1  0   0  1
111  1  0   1  0

ABCD  F3 F3' F4 F4'
0000  0  1   1  0
0001  1  0   1  0
0010  0  1   1  0
0011  1  0   0  1
0100  1  0   1  0
0101  1  0   1  0
0110  0  1   0  1
0111  0  1   0  1
1000  0  1   1  0
1001  1  0   0  1
1010  1  0   1  0
1011  1  0   0  1
1100  1  0   1  0
1101  1  0   0  1
1110  0  1   1  0
1111  0  1   0  1

F1 = xy + x'z'
F1'= xy' + x'z
F1 = (x' + y)(x + z')

F2 = x' + yz
F2'= xy' + xz'
F2 = (x' + y)(x' + z)

F3 = BC' + B'D + AB'C
F3'= BC + A'B'D' + B'C'D'
F3 = (B' + C')(A + B + D)(B + C + D)

F4'= ABD + A'BC + AB'D + B'CD (written down directly from POS given)
F4'= AD + CD + A'BC (simplified)
F4 = (A' + D')(C' + D')(A + B' + C')
F4 = B'D' + AD' + A'C'

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